Introducing VRay Single 01

7/31/2019 Introducing VRay Single 01

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Cinema 4D rainingIntroducing VRay

A short guide to the settings o VRayForC4D

Stuart Lynch

Te C4D Vault presents


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ZIP ARCHIVE PASSWORD

SherbetLemoncase sensitive

Project les can be ound at

http://www.thec4dvault.com/down/vrayguide.zip


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TeC4DVault(.com)TeC4DVault.com was created by Stuart Lynch and provides Cinema 4D training, resources and samples or the C4D community. Stuart is a veteran Cinema 4D user with over 10 years o proessional exprience in the industry and several years providing instructional inormation to intermediate users.

Tis rst in a series o new short instructional pd s is aimed at providing the user with enough inorm

tion to digest without becoming overwhelmed. It highlights the backend o VRay and relates the impotance o understanding the settings that make VRayForC4D one o the best render engines around.

Over the coming months, TeC4DVault pd booklets will cover a wide variety o topics, providing a rand reliable way to learn Cinema 4D.

I hope you enjoy this rst addition and learn a thing or two about VRay in the process. Tanks or readin

Stuart Lynch

http://www.project1media.com

Please make a minimal donation to keep the resource alive.*See Donate section at www.thec4dvault.com


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I you were to search images.google withthe term VRay, one o the rst thing youllnotice is the abundant usage o the PhysicalSun/Sky setup.

Its a practical solution or lighting interiorsand will serve as our rst demonstration othe VRay engine at work.

In gure 1.1 we have the Sun lightparameters

which allow us to make changes to the Sunsintensity and its physical properties.

For this example were simply going to acti-vate the Sun/Sky and become amiliar withthe lighting it provides or the scene.

gure 1.1

In gure 1.2 Ive created a primitive cube wi2 segments on each side. Te geometry habeen edited and 2 simple openings have bextruded on the most distant polygons.

Te editor camera has been positioned incenter o the screen and Ive exaggerated teld o view slightly to include both openings.

gure 1.2

gure 1.3

o complete this portion o the setup, Iveadded a simple target light gure 1.3.

Chapter 1: Introducing VRay - Te Sun and Sky


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Its time to turn our C4D shot into a VRayscene. First activate VRay in theRender Settings - gure 1.4

gure 1.4

Youll notice now a new VRay Bridge Optiongure 1.5 has appeared or VRay on the lef

hand side

gure 1.5

Clicking the VRayBridge option will reveal

the many VRay bridge parameters gearedtowards the nal rendering setup.

Next click on the tab that saysIndirectIlluminationgure 1.6and check the rst box that saysGI ON gure 1.7

gure 1.6

Youve now successully activated VRay anand activated GI.

Feel ree to test the render.

gure 1.7

gure 1.8

Now that youve witnessed the true powerVRay, you might want to take it to the nexlevel.

Right click the light object in the ObjectManager and scroll down to the VRay tagFrom the list, youll want to add a VRayLitag. gure 1.8.

gure 1.9

Te inormation required to manipulateVRay lights specically is now contained the VRay light tag or uture reerence. gu1.9 You can double click this tag at any timto retrieve this set oparameters.


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Te VRayLight tag contains a lot o impor-tant unctionality and well become amiliarwith all o the options as we progress.

For now, our intention is change the targetspotlight to become a Sun light with aPhysicalSky

In the option Light typegure 1.4 Change roma Spot light to an Innite light.

Also checkEnable shadows

gure 1.10

Te light now is as it suggests, an innitelight and not yet a Sun Light. In order or thelight to become a Sun Light we must clickthe Sun Light tag and make a ew adjust-ments

gure 1.11

In gure 1.11 I have checked the boxes PhysSun and Physical Sky.

A test render gure 1.12 will now reveal a roilluminated by the physical qualities o thesun and sky together.

Focussing on the details o the render, itspossible to notice that theres a slight aw the accuracy o the lighting.

Te sunlight that enters the room looksoverexposed, yet the subsequent light all-o is too dramatic and occurs too quickly

Meaning, the rest o the room is too darkwhen compared to the intensity o the sun

Maybe its that the scene needs a ll light perhaps weve missed the more GI bouncoption, aer all its an interior scene.

Not so ast!

Te solution in Color Mapping

gure 1.12


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Color mappingo make a point stick with his students, my college instructor would occasionally use proanity.So let me say that using Color Mapping in your workow will oen save your ASS!Tere are plenty o headaches to come, trust me, but with this simple workow youll avoid blown outlight sources that can make or break a render.

Its a straight orward concept to understand when illustrated with this amazing set o renders.

In gure 1.13 Te area light in this simple room appears to give of the correct light intensity andilluminates the portion o the room closest to camera. But at the source, the light appears nuked

In gure 1.14 I we dial back the lighting intensity a little, the light at the source appears to have corrected

itsel, but at the expense o less light reaching the back o the room.

gure 1.15

gure 1.13 gure 1.14

In gure 1.15 the light intensity is restored to the brightness ogure 1.13, color mapping is applied and thelight adequately reaches the entire space. Balance is accomplished.


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FORINDOOR SHOS.

ype: Exponential (some preer HSV exponential)Dark Multiplier: 3.6

Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2LinearWorkFlow- Check to ON

FOROUDOOR SCENES.

ype: ReinhardMultiplier: 1.5

Burn Value: 0.5Gamma: Between 1.8 - 2.2LinearWorkFlow- Check to ON

I youre not already aware o the implications o using a LWF - See the ollowing PDFhttp://www.pixsim.co.uk/downloads/Te_Beginners_Explanation_o_Gamma_Correction_and_Linear_Workow.pd

By deault VRay uses the Color Mapping type (menu option ype)Linear Multiplywith deault DarkandBright Multiplier values set to 1

You will notice several other ypes in this drop down menu.

ExponentialHSV ExponentialIntesity ExponentialGamma CorrectionIntesity GammaReinhard

Te most practical color mapping ype or interior rendering is Exponential mode (or HSV Exponential)For exterior shots, it is recommended to use Reinhard

Te ollowing settings are a general guideline or what these numbers should look like.

You can use nd this unction in VRay settings under Color Mapping. gure 1.16

gure 1.16


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It wouldnt be air to ofer you thissolution without some idea o whatshappening behind the scenes. Aer all, youdid buy the book rom a desire to learn.

So i we apply the Indoor settings rom theguidelines on the previous page, we can draw

comparison to the original Sun/Sky render.

gure 1.17 is the original without color map-ping applied (Gamma 1.0)gure 1.18 in exponential mode with the guide-line values (3.6/1.8/2.0) (Gamma 2.0)

gure 1.17

gure 1.18

In gure 1.17 we have the issue where the sulight is not illuminating the scene correctlIn gure 1.18 the samples illuminate the shocorrectly and the light intensity is well balanced.

Te diference lies in the mode Exponen-tial, this prevents colors rom becomingtoo burned out and bright. Itll saturate thcolors as they reach too high o an intensi

Te darkness multiplier value increase to indicates that the original output o grey/blue will have be multiplied by 3.6, givingrise to the additional light and brightness the scene.

Te brightness multiplier is increased to 1Which indicates that although the exponetialvalue has reduced overall brightness, ican still be multiplied to compensate or tdip you see in gure 1.19.

You can consider it a compromise.

In gure gure 1.19 the brightness multiplie

is being le at its deault value o 1.0 and tsunlight would be too low in its intensity.

gure 1.19


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In VRay its important to use as accurate ameasurements as possible.Tis basic cube is 500cm x 200cm x 800cmand represents our small bedroom. gure 2.1

Chapter 2: Te test sceneIn this chapter well begin with a quick scene and will introduce the Physical Camera.

gure 2.1

In igure 2.2 Ive added 5 segments to the Xside o the model. Edit the model (hotkey C)

and move the editor camera inside o themodel.

gure 2.2

With the camera inside the model, select polygons and reverse normals so that theyacing inwards. (hotkeys U~R)

gure 2.3

Selecting two aces as shown belowgure 2Use inner extrude (hotkey I) and extrude(hoD) to create two window openings.

Here you could split the glass geometry olater (hotkeys U~S) or simply delete the twopolygons.

gure 2.4


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Switch to the point tool and rom theattributes manager uncheck Only select Vis-ible Elements

gure 2.5

In the op viewport select the polygons thatmake up the ront window and rear wall.Drag to the le as in gure 2.6

Repeat the process or the Right window as

shown in gure 2.7

gure 2.6

gure 2.7

Returning to the editor view, raise the lowportion o the windows up slightly. gure 2

gure 2.8

Select all the polygons on the foor plane a

extrude down slightly to create room or athin mouldingeature gure 2.9

Select all ceiling polygons, perorm a slighinner extrude and then a regular extrudeupwards. gure 2.10

gure 2.9

gure 2.10


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gure 2.12

In gure 2.12, extrude the ceiling polygons tomatch the mouldingextrusion.

Perorm a simple select loop commandwiththe polygon tool (hotkey U~L) gure 2.13 andExtrude slightly at 91

Dont be concerned i your shot is nothinglike mine. I your scene has two openingsorgive you.

Moving on.

gure 2.14 - est render or illustration purposes only

Select the wall polygons in between the win-dows and extrude. gure 2.11

gure 2.11

gure 2.13


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Find a place where youre happy with theviewport representation o your scene andadd a regular Camera.

fgure 2.14

Roughing out the lights

Add a arget Light and position yoursel inthe top view, try to fnd a placement or thetarget light where you would like the Sun toexist. fgure 2.15

fgure 2.15

Select VRayas your primary render enginein RenderSettings and as in the earlier ex-ample, checkGI on in the IndirectIllumina-

tion tab.

Add a VRay Light tag to your arget light,checkenable shadows, change rom spotlight to infnite light. In the SunLight tabactivate the Physical sun and Physical Sky.

Returning again to the editor view andensuring you have you camera selected. Ryour frst render. fgure 2.16

fgure 2.16

Clearly not enough light entering the roomon this angle. Tis issue o balance is morprominent than in my initial examples.

Its time to applyColor Mapping to bring room to lie. fgure 2.16

fgure 2.17

REMINDERFORINDOOR SHOS.

ype: Exponential (some preer HSV exponential)Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2LinearWorkFlow- Check to ON

A small improvement.


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Bringing the shot to lie.

From the Material Manager add a newVRayAdvanced Material to the scene. gure 2.18

So ar we havent included any materials in our scene. VRay responds to color change quite dramaticalas does color in the real world. I we add a tiled wood texture to the oor, the bounced light rom thewood and its color values will have an aect on the scene. Lets explore urther......

gure 2.18

Assign the newVRay Ad-vanced Material to your cubeobject in the OM (objectmanager). gure 2.19

Ive named my material basegure 2.19

Double click the Material WoodIn the Diuse Layer - exture map slot.Load a wood tile texture gure 2.21

Create a second VRay Advanced Materialand change the name to wood

Select all oor polygons and drag the woodmaterial over the polygon selection gure 2.20

gure 2.20

gure 2.21

In the OM select (click) the woodmateriatag. In the Attributes Manager, change theprojection mode rom Spherical to Cubic

Using the texture axis tool and the scale togure 2.22 Scale the wood texture to t yourscene.

gure 2.22


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Running a new test render, notice how thewooden oor is afecting the lighting in therest o the scene. gure 2.23

gure 2.23

Make a ew adjustments to your camera po-sition and to the SunLight and try to balanceboth lighting direction and composition.

gure 2.24

gure 2.24

In this next phase o scene creation, wellstart blocking out some objects with simplegeometry to get a better eel or composition.

Place Cube primitive objects and positionthem where the bed, side tables and cabinetwould potentially be.

Te presence o more white objects haschanged the dynamic lighting o the sceneonce again. gure 2.25

gure 2.25Adding some additional materials withvariations in color (preerably chosen to represenhow you imagine your scene) were able to improupon the overall eel o the shot. gure 2.26

gure 2.26

With all o these geometry additions youmay have noticed that the light in the roomhas taken a signicant dip in brightness.On the next page well discuss the PhysicaCamera and how to implement photograpvalues in order to restore the balance.


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Introduction to the Physical cameraTe Physical Camera in VRay allows us to reproduce theparameters o a real world camera.o improve our scene without urther adjusting the Color Mapping or the deault lighting intensity o Sun, well implement the Physical Camera and make use o its eatures such as ISO and FStop.

From the OM select your scene Camera,right click and apply a VRay Physical Cam-era tagrom the VRay Bridge ags submenu.gure 2.27

gure 2.27

I you test a new render you would noticethat no signicant changes have occurred.

Tough the deault settings o the VRayPhysical camera provide a similar result,they dier greatly rom a camera that has noPhysical properties.

Te proo is in the numbers.

In the VRay Light tag under the Sun lightparameters youll see two separate values.

Intensity multiplier or Phys Cam : 1Intensity multiplier or Std Cam: 0.037

Te sun intensity is divided by exactly 270to work at the deault value o the standardcamera.

Its good practice to use the Physical cameor allo your scenes.

Well look more closely at comparisons inlater chapter, or now were occupied withincreasing the exposure values o our scenwithout making any adjustments to lightintensity.

Click the VRay Physical Camera tagUnder the ab - Lensparameters.

Scroll down to Film ISO and change thevalue rom 100 to 400

A test render produces this result gure 2.28

gure 2.28

gure 2.26 Old result or comparison


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An increase in Film ISO values rom 400 to1600 gure 2.29 increases the lm sensitivityurther and subsequently alters the bright-ness o the scene.

Changes in F-Stop values can also be madeto compensate or brightness.

Shutter speed can typically be le alone,although it is an important value when intro-ducing motionblurinto your workow.

gure 2.29

I youd like to continue with your scene andstart placing actual geometry or re-working

the blocked outmodels to become realisticxtures in the room. Feel ree.

gure 2.30

In gure 2.30 Ive added a new bed and a somsubtle blurry reections (reereed to as Glossinreections in VRay) to the wood material.

Although Ill shortly be introducing moredetailed inormation on the VRay AdvancMaterial, i you want to add this efect to

your current scene, Ill show you the quickway.

Activate a Specular layer in your wood marial and input a Glossiness reection valu0.8.

gure 2.31

gure 2.32

A couple o tweaks later and some stock

models rom my collection. gure 2.31

Few renders looks complete without a littpost work. gure 2.32


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Chapter 3: Introducing VrayBridge render settingsQuality is very important when we think about nal renders, but this shouldnt always come at the coso lengthy render times. Trough exploring VRays render settings well learn to tweak theparametersorder to get the best results in an optimal amount o time.

In this section well optimize the VRay Render Settings and then explore the method behind the mad-

ness. Open the example bedroom.c4dopen rom www.thec4dvault.com and lets begin.

gure 3.1

From the ab Indirect Illumination (GI)select 01_IR-LC_very very ast rom the GI

Preset list

IRreers to Irradiance MapLC reers to Light Cache

In the Primaryand Secondarybouncesyou can see the two modes being selected.With this setup the Light Cache will be cal-culated rst. gure 3.3

gure 3.2 gure 3.4 Te amiliar Light Cache calculation

gure 3.5

At these low settings rendering with LightCache as both a rst and second bounces

as with gure 3.5 would produce some oddsplotchy results.

Although with the correct values, this technique is equal to Unbiasedrendering.GI Preset 19_LC_LC_PP_unbiased is seup to render in this way.

Te Light Cache is an approximation o thglobal illumination in the scene. gure 3.4

gure 3.3


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Aer successul completion o Light Cach-ing, the Engine then begins computation theIrradiance Map.

A simplied explanation o the Irradiancemap is to imagine apoint cloudthat origi-nates rom the Camera andprojects out-

wards into the scene.

In gure 3.6 Im using a VRay resourcecalled IMapViewer.exe. With this were ableto view the resulting IR map in its raw orm.From the camera perspective in the bottomle corner, its quite easy to visualize the jobo the Irradiance map. Tere are no samplesoutside o the Camera view and so we can

conclude, it only samples what it needs tosee.

gure 3.6

gure 3.7

Te simple scene below is the resulting gure3.7 render rom the above calculation.

Te more rened the Irradiance map settare, the better it is able to assist in renderismaller details. Tis also comes at the cosrender time.

Objects such as walls and oors require vlittle IRsampling, but a detailed ornamen

on a table needs more rened samples toreach the tight spaces.

Providing adequate coverage is much lesso a struggle than it may seem. VRay comloaded with presets that provide an excellstarting point in most cases.

gure 3.8

Te DMC Samplergure 3.8 is the VRaycontrol Room. Tese 4 values basically de

termine how VRay uses its adaptive sampwhich Ill explain later.

Te engine itsel uses deterministic MontCarlo sampling (DMC), which is a highquality approximation GI algorithm. Tebetter the settings, the more reliable and acurate that approximation becomes.

Its not imperative that we learn exactly ho

the backend o VRay works. Whats impotant is that we understand how these vastamounts o values will afect our end resu

Well need to break them down a little inorder to make sense o them.


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Back to the DMC sampler, add the valuesrom gure 3.10

gure 3.10

Adaptive amount will be le alone.Minimum samples have been reduced rom8 to 4Noise threshold was in an okay place with

0.01, so we wont touch that either.Global Subdivs multiplier is set 0.5, downrom 1.

In the tab Indirect Illumination (GI) clickthe Irradiance Map arrow to reveal more tings gure 3.11change the Hemispheric SubD

Anti Aliasing (AA)is another important ac-tor in determining nal VRay render quality.

Te Adaptive DMC Anti Aliasing mode gure3.9 and the DMC samplergure 3.8 are tiedin very closely, especially when comparedto other Anti Aliasing techniques like the

Adaptive Subdivision sampler

gure 3.9

gure 3.11

gure 3.12

gure 3.12

For Hemispheric SubDivision enter thevalue: 30For Interpolated samples enter a value o:

We can ignore the other settings or now.

gure 3.13

Still in the tab Indirect Illumination (GI)

click the Light Cache arrowgure 3.11

In here well simply be changing the SampRatio rom 1/2 to 1/16 gure 3.13


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Finally under the Options tab un-check theGlossy Efects to prevent any blurry reec-tions rom calculating gure 3.14

gure 3.14

Now we can run our rst preview qualityrender at ultra ast speed.

gure 3.15Te result is awul, yet it took only 12 sec-onds to render at 1280x720.

Tis very low setting is a perect place tostart rom i youre blocking out the sceneand need to make quick decisions.

Weve barely scratched the surace o thisnew inormation and I have you dialing innumbers that probably make no sense to ywhatsoever.

My instructional method is to teach throuexample. Once youre amiliarized with thprocess it will start to become second natu

Yet that is only part o the equation.

It is also important to have a basic under-standing o why each value works the waydoes.

In this next section well adjust or a nalrender a along the way Ill point out somethe method behind the madness.

gure 3.16

I your render happens to look as it does igure 3.16, it would be because you havent yapplied Color Mapping. Not mentioning ithis was an intentional test.


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Indirect Illumination - Irradiance map

empting as it may appear to ignore this section and rely upon VRays preset values, I would recommeagainst it. Presets only solve hal o the equation, they have no aect on AA or the DMC sampler andtheyre not intended to provide a complete setup or your scene.

Instead see thepresets as a good starting point. TeMedium quality presetis sufcient or most projectand only requires a ew minor adjustments to bring it up to speed.

When rendering a GI shot in VRay, theengine requires two solutions to produce ac-curate GI results. Tose are the PrimaryandSecondary bounces.

In gure 3.18 Iveturned osecondary bounces

and le the Primary bounces as: Irradiancemap.

With only one GI engine actively calculating,a correct GI solution has not been possible.

Tis is visible as the dark areas in the image.

Each o the approximation methods has itown very specicparameters.

Te IR map (IR map - Irradiance map)has manoptions or the management o correctlycalculating samples, sample accuracy and

tail enhancement. It also has a section useexclusively or animation,.

Te rst twoparameters you come across Min rate and Max rate. Tese settings relato the size o the IR map calculation.

Te Min value determines the resolution the frst GI pass. Te Max value determinthe resolution or the lastGI pass.

A Max value o 0 would imply that theresolution o the last GI pass is equal to thdimension o your scene resolution.

A value o -1 is equal to hal the resolutionthe dimensions o your scene resolution.

A Min value o :-4and a

A Max value o: 0,

....would create 5 passes during the cachinprocess. ( -4, -3. -2, -1 and 0)

Te Maxvalue 0 is typically not needed oless complex scenes.

gure 3.18

So ar weve used only two o the vepossible GI engines in these slots. Te presetvalues highlight other combinations, thoughthe IR and LC is our ocus or the time be-ing.

As Irradiance map is our primary bounce,well introduce its settings rst.


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You could ask why not just have a Min valueo -1 and a Max value o -1? Or a xed value?

Te smaller values in the Min setting (-4 orexample) are important or sampling the biggerdetails (walls etc). Te larger values in Max (-1or 0) are or sampling the ner details.

You would rarely encounter a need to use apositive value like 1 in the Max setting. I itoccurs to you to do so, it would be wise tolook elsewhere beore concluding that this isthe solution to your rendering woes.

Min andMaxhowever, are only part o thesolution.

In gure 3.19 the low settings Ive deliberatelychosen are creating very obvious splotches.Tis suggests that are settings are way o themark and need to be re-worked.

A Hemispheric SubDivision is part o theradiance map and is used to determine thquality o individual GI samples. Relatingonly to the samples o IR map in this case

We can look here to improve upon our IRmap caching process. A good starting pla

when attempting a nal render is around 50 mark.

Values upwards o 150 are not unheard oproblematic renders, though typically yound that 50-80 is adequate.

Interpolated samples reers to the interpotion o the IR map samples. Tis calculatilook towards the range o existing data an

attempts to rene that process urther.

With this setting - oo high a value is likelto blurthe solution, oo low and the sampwill receive no interpolation.

So we can determine that some Interpolatsamples are necessary.

o compliment the Hemispheric SubDivi

sion, a value o approximately 15-30 is usually always sufcient.

gure 3.19

Rening the IR map settings is how weprevent splotches and other inaccuracies. Itensures that this approximation method (our

primary light bounce) will provide enoughsamples to assist in a awless nal render.

Note: Over estimating the values can cre-ate unnecessarily long render times. Underestimating causes artiacting. (Not to beconused with noise)

gure 3.20

Look to the next page or some compariso


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In all o the above examples Hemispheric SubDivision has a value o 50

In gure 3.21 the Interpolated samplesvalue is 1, which at close inspection is too ew samplesIn gure 3.22 the Interpolated samplesvalue is 100. At this value the samples tend to become blurred.In gure 3.23 the Interpolated samplesvalue is 20. Tis is practical amount or most renders.

At this scale it is perhaps difcult to see a huge dierence. Also any remaining noise issues youre seeinwould then be an issue with the DMC sampler and not the IR Map.

gure 3.21 gure 3.22 gure 3.23

Tere are clearly other settings in the Irradiance mapparameters, yet in the interest o not becomingbogged down with too much input, Ill only briey highlight their usage.

o the le o the Min/Max rates lie the Intensity Treshold, Normal Treshold and Distance Treshold

Tese settings reer to individual sensitivities to light intensitychanges, surace normalchanges andchanges in the distance between suraces. I would leave these values alone and let the provided preset

values guide you until you become more amiliar.

Tere are occasions with objects such as thin blinds where adjustments to these settings will benet yrender.

In the Detail enhancement section are a couple o additionalparameters.Tis unction as the name implies creates additional detail(to small detailed objects, not really useul in a typical sceUtilizing this process will orce the GI algorithm to compute with Brute Force GI in places that are dicult or the IR map to reach.

When using this unction it is oen necessary to consider lower overall IR Map settings.With this option checked were dependant upon Detail enhancement to enhance our render, the remaiing settings would thereore only need to made be suitable or coverage o the larger objects.Note: Tis is because large objects such walls/ceilings typically get adequate coverage from fewer samples.

In my proessional career I have used the Detail enhancement unction no more than 3 times.


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Indirect Illumination - Te Light Cache.

Te light cache (once again) is the approximation o global illumination in the scene.

Spot3D.com Te light cache is built by tracing many eye paths rom the camera.

gure 3.24

I have to admit the rst time I saw thismenu, I elt a lot less threatened by it than Idid the Irradiance map options.

In our current IR - LC setup were depending

on the Light Cache portion o this solutionto computer the secondary bounces.

In gure 3.24 the Overide LC subdivision box ischecked by deault.

Te value inside the samples ratio (drop downmenu) and the Subdivision amount (greyed outbox) dier only in mathematical approach.Tey both determine how many paths are

traced rom the camera.

Un-checking this box and manually insert-ing your own value is recommended, espe-cially ithe secondary bounces require moreattention.

Te number o paths traced rom the camis the square o the subdivision value. 100equals 1 million paths. 2000 is 4 million 10,000 is 100 million.

Te Samples Ratio values are based on thresolution o your scene. In the case o the1/1 setting in a scene thats 1280x720, theLight Cache would produce 0.9 million

paths.

gure 3.25

In gure 3.25 I used a Sample ratio o 1/1 at1280x720, implying 921,600 samples.Te light cache took 28 seconds to compu

gure 3.26

In gure 3.26 I used a 960 samples in theSubdivision box. 960 = 921,600 samplesshould come as no surprise that the calcultion took exactly the same amount o time


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Tere are some instances where youll needto go beyond the 1/1 Samples ratio amountand manually enter Subdivision values.Tough 1/2 is quite sufcient in most cases.

It is imperative to use a higher value duringanimation, but rare to exceed 4000.

With scenes outside o the typical PhysicalSun/Sky setup, where perhaps were using anabundance o light sources . Te subdivisionvalues will benet rom a boost.

gure 3.27

Weve covered the essentials and Ill providea very brie explanation or the remainingsettings.

Sample size determines the spacing osamples in the light cache. (Leave alone or now)

Passes calculates the light cache separatelyon each thread o your cpu. (Useul or animation)

Store direct light. Tis option stores andinterpolates direct light. Tis can be useul iyoure using and IR - LC setup.

Use camera path. Tis is or tracing the Lightcache along a camera path and is benecialor animation.

Adaptive tracing. Stores additional inor-mation about incoming light or each lightsample.

gure 3.28

Reconstructionparameters.Teseparameters control how the light cais used in the nal rendering, aer it hasbeen calculated.

Prelter Checked on - Prelter will be usePrelter is applied once the cache is com-puter or loaded rom disc.

Prelter samples More prelter samplesequals a more blurry and less noisy cache

Filter type. Tis is or tracing the Light caalong a camera path and is benecial oranimation.

Use light cache or glossy rays. I this optiis on, the Light Cache is used to computeglossy rays as well normal GI rays.

Tis option can speed up rendering o scenethat have blurry refections by a signicantamount.

Enable LC retrace. Tis option assists VRain preventing light leaks at the expense oslightly increased calculation time in the IMap.

Retrace threshold. Tis value can be used conjunction with use light cache or glossrays to help VRay dynamically decide whand where to use the Light Cache.


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Page 32

Te DMC SamplerHaving covered two o the possible GI engines and how their individualpasses contribute towards thequality o the nal render, we need to talk about the big guns! Te DMC Sampler.

You can think o the DMC sampler as a global quality control.Tis group o 4 settings play a very important role in the rest o the workow.

gure 3.29

During render time, the DMC sampler islooking out to your scene or additionalsamples.

Tese rays are computed in such a way thati the values are too low, they will produce anoisy result. gure 3.30

gure 3.30

Values rom almost every part o the renderengine are coming in through this channeland being processed here.

Whenever you create a light, a blurry reec-tion, use Depth o eld or Motion Blur(toname a ew), youve actually been providing theDMC sampler with more samples and inor-mation about the scene.

Looking at an Area lightsparameters (VRaLight tag), it reveals that the DMC sampler wbe receiving 8 Subdivisionsamples rom thlight source. gure 3.31

Te actual amount osamples, is the squaro the subdivision value / 8 subdivisions = 64samples

gure 3.31

Te DMC Sampler can look at a series othese samples and determine that it hasenough inormation to notuse them all.

Tis is the role o the Adaptive amount.

Lets imagine the DMC sampler sees 100samples or the entire scene. I we chose anadaptive amount o 0.8, the DMC samplerwill always use 20 o those samples. Teother 80% will be considered internally bythe engine, but not necessarily used.

Control over this unction is decided by thEarly ermination Algorithm


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With an Adaptive amount o 1, we hand overcontrol o all o the samples. (Fully adaptive)

With an Adaptive amount o 0, All100samples will be used without considerationor the Early ermination Algorithm. (Notadaptive)

In most cases, the deault value o 0.85 orthe Adaptive amount is more than sufcient.

At 85% adaptive, this may seem like wereleaving too much to chance, giving too muchcontrol to the DMC sampler. But VRayhandles the process very smoothly and itsnot oen necessary to go below 70% (0.7)

Noise Treshold.

TeAdaptive process communicates directlywith the Noise Treshold amount. Tis valuedetermines the amount o noise that is ac-ceptable beore it can tun its attention to thenext pixel in the calculation.

gure 3.35

gure 3.32Noise threshold has a value o 0.0gure 3.33Noise threshold has a value o 0.1gure 3.34Noise threshold has a value o 1

A value between 0.01 and 0.004 is a goodrange or nal renders.

When the Noise Treshold is 1, the DMCsampler is satised that the desired amouno samples has been met while its still producing a very noisy value. Tis amounts tan incredibly ast, but noisy render.

Te DMC sampler requently needs moresamples rom the external elements that adifcult to compute.

A metal material that has blurry values(Glossiness subdivs) such as Brushed steel oen require more samples to achieve noireduction and a quality result.

Instead o trying to compensate or this inthe DMC sampler, we would simply increthe Glossiness Subdivsvalue in the speculchannel o the Vray Advanced material tovalue higher than the deault 8. gure 3.35

gure 3.32

gure 3.33

gure 3.34

Similarly, a single Area light that clearlystands out rom the others as having toomuch visible noise, would also benet rosending more samples to the DMC sampl


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Page 34

When a single object causes an issue, its im-portant to look at its individual subdivision

parameters to resolve.

It would be a shame to spoil a good balancedrendering solution and shoot or an overallincrease in quality on account o one prob-

lematic object. Tis wouldnt be a practicalway to work.

Looking again at gure 3.29 we have 2 settingsremaining to talk about, and both o them atthis point should be easy to comprehend.

gure 3.36

Minimum Samples

Min samples equals the minimal amount osamples that the DMC sampler will computebeore terminating the algorithm.

Note: Te deault 8 is once again squared

to imply 64. It also intentionally matchesthe deault number or all subdivision based

parameters.

Global Subdivs multiplier.

I an overall quality boost is required oreverysubdivision basedparameter, this is agood place to dial in some numbers.

Te deault value o 1 implies that everyvalue will remain the same as the input value(or example: Glossiness Subdivs: 8)

A increase to 1.5 would provide a 150% in-crease to all o these values.(Increasing the:Glossiness Subdivs: to12)

Ive introduced you to 2 GI engines so athe combination o which enables VRay tprocess your render.

Te IR + LC method is a popular choice aas an introduction to these practices wasworth highlighting them side by side.

Some other useul combinations are highlighted in the presets.

I.e;Lightcache +Bruteorce / IRradianceMap + Bruteorce.

Brute orce computes every single shadedpoint separately and independently o othpoints, (while other approximation methods considetheir neighbor in determining calculation). Whilehighly accurate this method can also be vslow.

Te subdivision parameter here will alsotalk to the DMC sampler in the same waydiscussed earlier.

Ray depth controls the number o bouncethat will be computed, but is only availabli Brute orce is chosen as a secondary GIengine.

Photon maps are occasionally useul or interiors scenes, but this is an older methodapproximation and I typically avoid it.

Spherical harmonics is notyet properlyintegrated into VRayForC4D and should avoided.

Brute orce, Photon maps, or

Spherical harmonics.


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Page 35

Im certain youre all amiliar with the practice o using Antialiasing in your scenes.VRay eatures 3 types o image samplers (antialiasing methods) and each one difers slightly in approa

We have the Fixed rate sampler, the Adaptive DMC sampler and the Adaptive Subdivision sampler.

Choosing the right image sampler is determined by the individual scene and there are diferent considations or each approach.

Antialiasing

Fixed Rate sampler gure 3.37

With this method, the sampler takes a xedrate o samples per pixel. Te subdivisionvalue is squared as with other subdivisionparameters. 1 =1 / 2=4 / etcA value o 4 would indicate that 16 sampleshad been taken per pixel.

Tis sampler is simple and predictable in abroad range o antialiasing tasks, but the na-

ture o a xed sample can equal slow peror-mance in some cases.

Note: Tough not be ignored, I would recom-mend one of the other two choices based onmy experiences with Fixed rate sampling.

gure 3.37 Adaptive DMC sampler gure 3.38

Tis sampler takes a variable number osamples per pixel based on a Min and Ma

rate.

It can also use the threshold set in the DMsampler to determine i more samples areneeded. (vs manual entry in Treshold amount)

Tis method is best or scenes that use a looblurryefects and is the preerred imagsampler or DOF and Motion blur efects.

Note: It is rare to have to increase the Minlevel higher than 1, other than scenes that aproblematic.

Using Show Samples is a way to preview tantialiasing setup prior to nal render.

gure 3.38


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gure 3.39

Adaptive Subdivision sampler gure 3.37

O the 3 methods, this is the only samplerthat can undersample (take less than 1sample per pixel).

In scenes that dont rely on blurry eects,

this is the preerred image sampler or bothits speed and reliability. However, in thepresence o these eects it can perormworse than the DMC sampler.

See below or comparisons.

gure 3.40 - Using the Adaptive Subdivision sampler

gure 3.41 - Using the Adaptive DMC sampler

In the renders rom gure 3.40 and gure 3.41 Izoomed in to 800% to highlight the dierences between the Adaptive Subdivisionsampler and the Adaptive DMC sampler.

Te render times were seconds apart andthe Min/Max settings identical (with no un

sampling in the Adaptive SubD sampler)

Te metallic device has a blurred metalsurace and its clear that in this round, thAdaptive DMC sampler did a better job.

Tats not to suggest that the DMC samplis always the clear winner. Te reliability o

Adaptive Subdivision sampler in the abseno blurry eects can add signicant speedincreases to your scenes and should not boverlooked.

Experimentation is key.

Antialiasing lterIn VRay as with other render engines,

Antialiasing lters can be applied. Tese amethods or sharpening or blurring valuedependant on your needs.

Tese lters are integrated into the samplprocess and do have an aect on render tiFor example a sharpening lter like Catmrom and Mitchell-netravali may cost you ew additional seconds when compared toblurring lter like Box, Area and Gaussian

and Area.

Note; Tese lters are not the same as applying sharpening/blurring lters in post. I worecommend using one based on your needsall times.


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I you want VRay to create high quality images that dont take orever to render, then we already have othing in common.

o achieve this, I requently tell my students that the best starting point is rom lower/medium qualitypresets. From here youll be able to discern what part o the render needs your attention the most. Is itsplotches on the walls? Ten look to the IR map. Or are the walls ne and its some nuisance ornamentwith a bump map giving you grie? Ten look to its material setting, the nearest light source, or bettermanage the antialiasing settings.

Tat may seem like a common sense approach, but i I got a dollar or every time somebody sent me ascene where theyd randomly entered 0.001 in the Noise Treshold to resolve a simple issue,Id be rich

Tat value may well have xed the issue, yet they inadvertently made the rest o the scene more complcated than it needed to be. On inspection its usually obvious that they were only trying to improve upoa couple o small problems.

Similarly theres a list o preset values known as Universal VRay 1.5 Settings that people rave about.You can see the appeal right away, although i you use these settings be open to the possibility o waitinaround or a long time.

Its my hope that I explained this process with relative clarity. I you do have any unresolved questions theVRayForC4D manual ofers very precise examples o why each setting perorms the way it does.

Wrapping up


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Chapter 4: Vrays materials

Whatever your choice o render engine its good practice to have a test scene or trying out materials.In this chapter well work with such an environment and introduce Vrays BRDF material system.

gure 4.1

Open the scene le test_stage.c4d gure 4.1

gure 4.2

Te scene uses three area lights and somebasic geometry, it also renders very quicklyor ast eedback.

Create rom the materials manager, a newVRayBridge - VRay Advanced material

A VRay advanced material has ar more

options than a standard C4D mat. Te vasmajority o materials youll set up in VRayare relatively straight orward, though witthis much exibility, theres a lot o room complexity and creativity.

Te material editor eatures many settingsthat youre probably already amiliar withDiuse (color), Bump, Material weight(alpha), Luminosity layer (Luminance) an

Specular layers (a mix o C4Ds reectionand secularity settings), Reraction layer(transparency)

gure 4.3


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Page 39

Tere are 5 Specular layers in VRay, this allows orthe creation o materials with more than one specularquality, such as varnished woods, car paints and some

plastics.

Tese layers contain options or both ake specularhighlighting, or in the more physically correct way,which is to calculate specularity with glossy reec-tions.

Note: Ive introduced you several times to the term Glossy. It simpleimplies blurry refections, but is reereed to as refection glossiness

in VRay. (See Specular layer parameters)

In a Cinema 4D material, specularityand reectionare separate entities. In VRay there is the option to usethe Reection layer, though this is reserved or ob-jects with raw reection like water and mirrors. It alsodoesnt contain an option to include glossy reections.

Instead the Specular layer is where youll need toturn or the vast majority o your material reectivityneeds.

Tis layer contains options or a vast amount o specu-lar properties such as anisotropic suraces, blurry me-tallic suraces and precise control with resnel efects(refection viewing angle). gure 4.4

Specular layers

gure 4.5

In gure 4.5

Sphere A, the Vray Material is tracinonly the ake specular values.

Sphere B, is tracing both ake speculand blurry reections.

Sphere C, is tracing blurry reectiononly.

Note: In the real world, almost every object contains at least some specularity.

gure 4.4

VrayAdvancedMaterial


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For our rst material, lets activate a singleSpecular Layer and leave everything as de-ault. Apply the material to the sphere objectand perorm a quick render test. gure 4.6

gure 4.6

In the setting Specular Layer ransparency,

change the amount to 50% and test again.

gure 4.7

Te reduction o transparency has allowedor more o the reection rom this layer toshow. gure 4.7

For the next stage o this material test, addanother Vray advanced material and in the

diuse channel only, add a blue color. Applythis new material to the cube object.

Now returning to the rst materials Specularlayer. Scroll down to reection glossinessand add a value o 0.8. gure 4.8

gure 4.8

gure 4.9

A rendered results should now show a melike material thats been processed with boake specularity and glossy reections. gu4.9

gure 4.10

At the top o the Specular layer settings isoption or Specular ype. Change this roPhong to Ward. Te result should now loolike gure 4.10


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Page 41

Each Specular ypes computes in a uniqueway and provides diferent results. Blinn andWard are good choices or metallic efectsand they also render Anisotropic efectsmore accurately.

Back in the Specular layer settings change

the Anisotropy value to 0.5

gure 4.11

Te result gure 4.11 is not quite yet a Brushedmetal, but were establishing the workow inordered to create one.

For the next step, return to the Difuse layer(remaining within the metal material) and reducethe Difuse Color - Brightness amount to

20%.

Back to the Specular layer scroll all the waydown to the last ew settings and Check theUse Fresnel box and input 22 or Fresnel IOR(Index o reraction)

You will now notice that the Specular Layerransparencyoption is no longer available.Tis is because were using IOR to determine

reectivity.

In the Specular color at the top, add a Fresnelshader to the texture map slot. gure 4.12 In theshader settings, reduce the black to a lightgrey. Tis will prevent the scratched suracerom reaching the spheres edges.

gure 4.12

Lower the Anisotropyamount back to 0 ain the exture map slot below load in thetexture H_Brushed.png rom the texturolder.

Repeat this process as illustrated below ingure 4.13 - while also checking the invert bowhere appropriate.

gure 4.13


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Page 42

Weve provided VRay with enough inorma-tion to produce a semi-realistic scratchedmetal surace. Work can be done in thebump map channel to bring out extra detailsand a lot o time can be spent tweaking thevalues or a perect result.

Note: Te reason behind the inverted texturemap in the Glossiness reection is that in real-ity, the deeper the scratch, the more blurry itsreectivity would become.

Te result in gure 4.14 is ar rom complete,yet you have a good starting point romwhich to experiment urther.

gure 4.14

Using a similar technique in gure 4.15 to cre-ate a Galvanized metal, the dierences inblurry values vs more reective values areobvious.

gure 4.15

You may have noticed that in the Specularsettings I increased the Glossiness SubDivsion amount up to 30.

As discussed in the section on VRays DMsampler, this is an example o where thematerial needs to send out more samples

order to be computed with less noise.

Keep in mind that these sorts o materialsare usually quite render intensive.

gure 4.16 VRay Goldman

In both gure 4.16 and gure 4.17 you can see tvast amount o exibility available to you the Specular layer channel.

gure 4.17 Te Weasleys


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Page 44

Reraction Layer

Te Reraction layer is or the creation o optically transparent materials.

Tis layer can assist in the creation o standard glass, gems, uids, complex translucent eects, rostedglass and much more. Its parameters contain options or the accurate calculation oAbsorption, Blurr

eects, Dispersion and Sub Surace Scattering.

gure 4.12 - Color enhanced

Open example le test_stage_glass.c4d

Create a newVrayadvanced material and applyto the glass object.

Deactivate the Diuse layer and activate a

Reraction layer.

CheckSpecular layer 1 without making anychanges.

Render

Without any changes to the deault settings,

the Reraction layer provides us with a glassmaterial with an IOR(index o reraction) o 1.6

Adding a Specular layer to a glass materialis common practice, as glass always includessome amount o reectivity.

In the Reraction layer look towards theVolume Fog parameters and checkEnableVolume.

Leave the Emission color as deault blackand chose a very light orange/yellow or t

Volume Color. Finally increase the amounto 0.3 and render.

gure 4.13


Tis eect has added absorption propertieto the glass and it now has the appearancegreater volume.

VrayAdvancedMaterial


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Page 45

o simulate rosted glass, we would entera Glossiness value (0.6 in this example) in theReraction layer. As shown in gure 4.15

Variation in the rosted amount can beachieved by using the Glossinessexture mapslot.


Note: Tese eects can add signicantly to your rendertime and ofen require additional subdivision values torender accurately.

Te images below contain diferent examplesoGlossiness efects in the Reraction layer.

gure 4.16 Visa product shot

gure 4.17 Go Beyond

It is also possible to use the SSS parameterom the Reraction layer to simulate thetranslucent properties o hard wax, honeyplastics and other suraces that depend mon reraction or accurate results.

Te example rom gure 4.19uses the ollow

ing setup. gure 4.18

gure 4.19

gure 4.18

Note; o speed up the SSS calculation checkEnvironment og in the SSS parameters. Tstores the light directly in the volume.


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Page 46

SSS calculated as part o the reraction layer (as shown on page 45)is an accurate representation o a realworld translucent eect. While it can produce stunning results, it can also be notoriously slow to rende

A much aster approach is to use a VRayFastSSS2 material. Te parameters o which are available as anextension o the standard VRay Advanced material and as a standalone material called the VRayFastSSmaterial.

Its also possible to cheat translucent eects using the Vray2Sided material.(which well cover on page 48)

Te majority o your translucent material needs should be met by the Fast SSS option.

Sub Surace Scattering

gure 4.20

Open example le test_stage_candle.c4d

In this scene Ive simply added a VRay-FastSSS material to the cylinder shape, madea couple o adjustment to color and added atexture map.

Te result gure 4.20 shows a subtle hint otranslucency.

In the VRayFastSSS material settings, scrolldown to options and change the Single Scat-ter parameter rom to Simple to Raytraced-reractive.gure 4.21

gure 4.21

gure 4.22

Te rendered result is now noticeably dient. gure 4.22

Te original Simple mode approximatedtranslucency rom the surace lighting alo

Te Raytraced-Reractive mode traces thereraction amount based on the providedIOR.

Also notice that when VRay is computingFast SSS, its also adding an additional dar

pass that appears to isolate the transluceneects.

Tis is a special pass called the Illuminatiomap. It can be controlled in the prepass rawhich is set to -1 by deault. For higher reimages, a value o 0 is occasionally needed

VrayAdvancedMaterial and VRayFastSSS2 Material


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Page 47

Tis time well use the SSS layer in the VRayAdvanced material to make a semi accurateportrayal o a marble oor.

Open example le test_stage_marble.c4d

Te scene is setup with a marble texture map

and contains only a Diuse layer.

In the Diuse Layer change the DiuseLayer ransparencyto 40%. Tis will allowunderlying eects such as the SSS layer tomix with the Diuse Layer at the inputtedvalue.

At 100% transparency, this Diuse layer

would no longer render at all.

Activate the SSS Layer and try to match thethree shades o green rom gure 4.24

gure 4.23

gure 4.24

Change the Single Scatter parameter romSimple to Raytraced-Solid.gure 4.21

Te Raytraced-Solid mode will calculate/etimate the Volume inside the object.

Te material is starting to look a little bettbut its missingglossy refections and a bummap.

Activate a Specular Layer , checkUse Fresand input a value o 1.6 or the Fresnel IOamount. Next, input a Reection Glossinevalue o .095

Activate Bump and copy the Diuse Layetexture into this channel.

With no real bump inormation, you canincrease the value to 3. Tough this is notpractical approach or most materials.

Te result is ar rom perect, but sufce tsay it created the desired aect. gure 4.25

gure 4.25

gure 4.26


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Page 48

VRay2Sided Material

Making a lamp shade with the bulb obscured behind a layer o abric (as in gure 4.27) used to be a di-cult task to accomplish. Fully opaque materials simply werent designed to transmit light through thesurace in this way. Adding Diuse layer transparency(or alpha in C4D) didnt help matters either, as apercentage o the light would simply pass through the volume.

Te VRay2Sided material solves this old limitation by allowing us to have a diuser in VRay.A diuser soens light as it passes through a surace, essentially making it what we call translucent.

Tis material was created to address the need or thin translucent objects like paper, leaves, abrics, diusers etc, but its application can be much more experimental.

In gure 4.27 the lamp shade object highlights an example o how this material was intended to work.Illumination rom within the object passes through the material via translucency and displays the resuon the ront acing normals.

Te VRay2Sided material is controlled by two standard diuse materials (VRayAdvanced material) or theront/back acing normals and a ranslucency color to determine how much o the eect should comethrough.

Te VRay2Sided material ingure 4.28 eatures reective properties on its ront side. A separate object wa colored pattern light has been placed within the dragon model (via the Luminosity layer) and the resultcreates a glowing translucent eect. Tis behavior looks closer to a reractive SSS solution, but is actuacheated as the light is emitted rom the inside only. O course cheating in 3D is never a bad thing.

In gure 4.29 Im using the same approach but on a much bigger scale. Tis time Ive placed uniquely colored light objects within each skyscraper. Te Luminosity layer casts its rays outwards and are intendeto ake the lighting that would have otherwise come rom a traditional lighting solution. Tis was a tesscene, but also a very practical solution or visualizing cities at a distance.


Standalone material


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Page 49

gure 4.31

Open example le scene 2_sided_user.c4d

Tis simple setup has an area light, a thinplane object, a couple o props and currentlyno materials. gure 4.30

gure 4.30

I we the render the shot directly, youll see

that the plane object is obscuring the light.gure 4.31

Add a VRay2Sided material and apply it tothe plane without any additional changes,and it will now render a simple difuser.igure 4.32

gure 4.32

Te light has now penetrated the object asdetermined by the parameters in the VRa2Sided material.

Leaving the ront and back side options othe VRay2Sided material ree o supportinmaterials was a deliberate move. It illustra

that in the absence o a material channel,the VRay2Sided material will use a standagrey difuse VRayAdvanced material bydeault.

Additional control is provided by the ranlucencycolorsetting. By deault it is setto 50% grey which would allow an equalamount o the ront and back to show(depdent upon illumination values).

o let more o the Back side material showthrough, push the color closer to white. oretain more o the Front side material, briit closer to black.

You can also use color or a ranslucencytexture or experimenting with diferenttranslucent efects.

In the example le scene 2_sided_spherelampyoull nd the ollowing example gure 4.33and other experiments rom my collection

gure 4.33

Note: In order or the Front side material to show all, it must be illuminatedrom the ront. Its a common mistake to light only rom the rear and expecthe ront side to show.


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Page 50

In this short tutorial, Ill guide you throughthe workow needed to make the ake SSSeect used on the Dragon gure 4.28 (on Page 48)

Open example le 2_sided_buddha.c4d

gure 4.34

Te scene gure 4.34 has a the Buddha gureand three primitive objects tucked neatly

inside his body.Create a VRayAdvanced material and adda Luminosity layer. Apply a blue Luminos-ity color, leave at 100% or brightness andadd a value o 10 in the second box labeledAmount

In Luminosity Layer parameters checkCompensate exposure.

Note: Well be covering Luminosityon the next page.

gure 4.35

Name this material backlightand apply it tothe Null object calledInternal -We now have an internal lighting solutionor the Buddha gure.

Create a newVRayAdvanced material andname it OutsideIn Diuse Layer 1 checkUse VRayDirt

Add dark blue or the Occluded colorvia color channel. (See page 43 or help)

Add a light blue or the Unoccluded colora color channel. (See page 43 or help)

Finally add Specular layer 1 and make no ditional changes.

Next, create a VRay2Sided material and athe material called Outsideto the ront simaterial option o the VRay2Sided matergure 4.36

Finally apply the VRay2Sided materialto the Buddha gure and Render. gure 4.3

Tis backlit ake SSS eect has countless uand o course, it looks kinda cool!

gure 4.36

gure 4.37


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Page 51

VRayBlendMaterial

Te VRayBlendMaterial allows you to stack materials - It works in almost exactly the same way as manally stacking them in the object manager, but allows or better management in some cases.

Te process starts of with a base layer such a brick map or example, then additional materials are ap-plied as a coat material, this could be useul or peeling paint o a layer o broken concrete.

Various mapping techniques that have some Material weight (alpha) or Difuse Layer transparencyareuseul in determining to what degree the underlying material is seen.

Below are some examples o materials that have been layered with this technique.

In gure 4.38 an underlying rock material is coated with a slightly translucent coating o snow.

In gure 4.39 glass is afected by a ery layer and covered with a dusting o sand.

In gure 4.28 an organic rock is coated with a glow based efect based of a vertex map selection.

All very straight orward, but with amazing amounts o potential.


Layering shader - Standalone

Note: Tese fles are all available in the VrayBlendMaterial older.


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Page 52

VRayDisplaceMaterial

Te VRayDisplaceMaterial allows the usage oDisplacement maps in VRay.

Its possible to mix this material with a standard VRayAdvancedMaterial by stacking it to the right o tstandard material and choosing Mix textures rom the texture tag. Lets quickly explore.

Te ollowing example uses the Displacement type: 3D Mapping, which is suited to procedural eects.

Open example le displacement_user.c4d

gure 4.38

Create a standard VRayAdvanced materialand apply it to the cube.

Create a VRayDisplaceMaterial and alsoapply to the cube object (aer the rst mate-

rial)

Select the VRayDisplaceMaterial tagromthe object manager and checkMix exturesgure 4.39

gure 4.39

In the VRayDisplaceMaterials texture patadd a noise channelrom the drop downmenu. Click the noise channel and changethe type to Cel noise, nally increase theGlobal scale value to 250%.

In the VRayDisplaceMaterials parameter

change the amountto 10cm and check thebox Keep contunity. Render. gure 4.40

gure 4.40

In gure 4.41 Ive copied the Cel noise to thVRayAdvancedMaterials diuse channel,created a couple o layers with some noisevariation and have used VRayDirt (page 43

See ledisplacement_example .c4d

gure 4.40

Use Cubic projection (or both)

Check Mix textures

Select VrayDisplacementmaterial.


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Page 53

Te Displacement type: 2D Mapping,is used when an image based displacement map is available.

With this workow, you can maintain a low polygon count and depend on the displacement map to givthe appearance o millions o polygons at a sub polygon level.

In examples gure 4.31 - gure 4.32 the rendered

results shows that although the originalmodel only had 68,000 polygons, theyvebeen efectively turned to 3.4 million poly-gons with a displacement map.

gure 4.31 Octopus

Parameters.Te amount value (in both the 3D and 2D optioncontrol the maximum height o the displament map.

Te shi value species a constant amounthat the polygons will be shied relative totheir normalposition.

While Use deault parameters is checked, resolution or 3D displacement is controllvia the VRayBridge settings under Displament.

Te deault amount can be set too high ocertain tasks and should be experimentedwith or optimal results.

For more in depth eatures relating to you

displacement needs, please reer to the VRmanual.

Note: Its still possible to add a VRayDisplament Tag rom the object manager, althougthis is the old workfow and only remainsavailable or Legacy reasons (to support old

les).

gure 4.42 (zoomed in)

gure 4.43 (zoomed in)

gure 4.33 -is the 16 bit ti image used to createthe displacement.


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Luminosity LayerVrayAdvancedMaterial

Te Luminosity layer(rom the standard VRayAdvancedMaterial)provides light via sel illumination.

You can use sel-illuminated materials on objects to represent lights that dont need an actual light souAn example would be the LCD display on the ront o a DVD player, or the backlight or a PDA device

In VRay, the Luminosity layer also has an option to turn the eect rom a standard sel illuminated marial into a ull edged light source via the Direct Illumination option. Lets take a look.

Open example le sel_illumination.c4d

Te render gure 4.44 has 2 sel illuminatedobjects and a white Environment light.

Using the luminosity layer in this mannerdoes not provide adequate shadow density tobe considered a viable lighting solution.

gure 4.44 (8 second render)

I you add a Physical Camera tag to the avail-able camera, theres a drastic dip in exposure.gure 4.45

gure 4.45

o make the luminosity brightness adaptto the physical values o the camera checkCompensate exposure. gure 4.46Note: Tis is easier than guessing a new intensityamount each time we make a change in exposure vi

the Physical camera parameters.

gure 4.46

Check the box Direct Illumination.

Tis turns the material rom a sel illumi-

nated source to a physical light source.

Enter an Intensityvalue o 200 or Direct lumination parameters.

Also in the Environment tag rom the Vrabridge settings, increase the Background Evironment brightness to 50 to compensat

gure 4.47 (Zoomed in)


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An increase in Subdivision amount rom theDirect illumination parameterscan eliminateany unwanted noise. Tis process is sending

samples to the DMC sampler as discussed onpage 32.

Te Direct illumination methodis sendingout light rom all o its surace normals andcan be quite slow to compute, however tospeed things up its possible to checkStorewith irradiance map and have the lightsource compute during the IR Map cacheprocess.

Using this approach requires a slightly longerwaiting time during IR map creation, butshorter overall render time. It also comes at acost o a slightly decreased shadow density.

When the Direct illumination option ischecked the material now eatures light-ing properties almost identical to those o aVRay Area light.

Te Luminosity color channel and texturemap slotsremain efective or colorization o

the light source, but the other channels sucha difuse and specular would be no longeravailable.

Te result o the render should now look likeit does in gure 4.48



Direct illumination does not work with se

tion tags, instead the system will manuallyoverride and use standard sel illuminatioproperties.

In the case o a single object with geometryou wish to use or light (i.e a lamp and bulb one object), it is necessary to double click thselection tag(or manually select the polygons) aseparate the geometry via the splitcom-mand. Cinema 4D lacks a splitand delete

unction, so you would also be required toremove the remaining geometry rom theoriginal object.

Tis Direct illumination method can behighly benecial to your workow, but itis my recommendation to use it sparinglyand only in situations where a physical ligsource cannot accomplish the same task.

In gure 4.49 the IR Map was responsibleor the light source. A ull render reveals aslightly soer result when compared to thmore grainy direct sampling method.


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Chapter 5: Vray lightsVRay lights are dependant on scale, when designing a shot with realism in mind its important to respthe process and work roughly at the real world size o the object in question. Does this always involvegetting out a calculator and pre-planning? No, but the closer you are, the more likely your lights are tobehave as expected.

Vray lights also have physical parameters or accurate measurement o light.

Lighting actual scenes isnt a topic well be discussing at length in this short book, but well cover the bsics and get you up and running with a ew small example scenes.

A standard C4D light with shadow param-eters enabled will provide VRay with enoughinormation to render with a with the stan-dard Omni light option.

Te result is an underwhelming eect thatstypical o Omni lights when compared to theshadow density o an Area light.gure 5.01

gure 5.01 (rom example le VrayStudioOmni.c4d )

Adding a VRayLight tag to the pair o lightsand turning the deault Omni light to Arealight, a ew tweaks later things are starting tolook up. gure 5.02

gure 5.02 (rom example le VrayStudioArea.c4d )



Accomplishing this wasnt a simple case oturning on Area lights, i you note in gurethat the Deault (image) intensity had to bcranked all the way up to 200.

Te reason or this is because were still using Cinema 4Ds units, which really dontrepresent any real world values. Instead iwe switch the Intensity units to Radiance

(W/m/m/sr), we get a much more accuratrepresentation o their actual brightness. Ithis case, the area lights are 100 watts.

Note: Always remember to enableshadowswhen working with VRayLights. (Tis paramecan be ound in the VRay Light - Common tab.)


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In the VRay manual...

Quote rom http://vrayc4d.com/manuals/vrayorc4d-manual/common-tab - VrayC4D Group. All right reserved.(c) 2008-2010

Radiant power (W) - total emitted visible light power mea-sured in watts. When using this setting, the intensity o thelight does not depend on its size. Keep in mind that this is

not the same as the electric power consumed by a light bulbor example. A typical 100W light bulb only emits between2 and 3 watts as visible light.

Radiance (W/m/sr) - visible light surace power measuredin watts per square meter per steradian. When this setting isused, the intensity o the light depends on its size.

....the units are explained in a common senseway.

In the previous scene, the illuminationstrength or the light is heavily compensatedby the exposure settings ophysical camera.Without the physical camera in place, thescene would have been massively overbright.

In example le watt_the_hell.c4d I have a verysmall area light in close proximity to thesphere with the physical camera tag re-moved. Ive done this to view the lights intheir raw deault intensity state.

Tis small area light has a Radiance (W/m/sr) value o 20 and a Radiant power (W)value o 5.97.

gure 5.05 (rom example le watt_the_hell.c4d )

Increasing the size o the light gure 5.06, thRadiance (W/m/sr) value remains at 20but the Radiant power (W) value has nowincreased to 41.7

Notice also that with the size change coma dramatic shi in shadow density. Tis is

real world phenomenon o course and queasy to understand why this would happeLarger area lights typically require moresamples to render accurately.

gure 5.06 (rom example le watt_the_hell.c4d )

gure 5.07

gure 5.08

In gure 5.08 Ive changed the Area type toSphere. Well want to scale this down to reresent a bulb.


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As I decrease the Spherical Area light radiusto approximately 5cm, youll notice thatthe editor view becomes distracting andoverbright. Tis is a common nuisance thatrequires only a simple logical understandingto remedy.

gure 5.09

gure 5.10

VRay lights dont have allo parametersas they do in Cinema 4D. Teyre physi-cal based and wont respond to allo sizechange. So to remedy this overbright statesimply manually drag the larger sphereshandles and close them down to approxi-

mately the size o your light radius.

With this youre controlling the allo dis-tance and editor visibility/brightness o saidlight and not anything related to the actualrender.

You can manually do this in the standardC4D light setting by clicking the light andnot the VRayLight tag. gure 5.11

gure 5.11

gure 5.11 (rom example le a_bulb_o_sorts.c4d )

Another quick render gure 5.11, Radiance(W/m/sr) value o 401 and a Radiant pow(W) value o 41So you get the picture.

Personally I stick with the native Cinema

units or lighting, they dont represent anything but Im comortable with that work-ow. Its not imperative to learn about watage and luminous power etc, unless yourea position to light based on pre-existing dIts all about personal preerence.

gure 5.12 Is one better than the other?

Te choice to use Rectangular lights vsSpherical gure 5.12 one is a question o whright or the job - Tey have uniquely di

ent ways o casting shadows/light and shorepresent the kind o light youre lookingto cast into the scene. Tough I nd thespherical light to be highly versatile in a loo cases, the rectangular shape is good orwhole range o lighting situations.


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Area Light - Light portalsWeve taken a quick look at Area light settings, now well dig a little deeper

gure 5.13

In gure 5.13 we have a typical Sun/Sky setupwith a very small opening. Tis is allowing alittle light to enter the room, but not enoughsamples are reaching the interior or a qual-ity result. Te rst idea would be to totallymax out the IR map, DMC sampler settingsetc, but theres a simpler way to approach thiswith a Light Portal.

Open scene Small_Hole.c4d and i youd like torender to the picture render or comparison.

First thing to notice in the scene is an AreaLight that has been turned of. Opening the

light parameters via the Vray light tag revealswhat looks to be only a standard area light,however the property Light portal has beenswitched rom Normal to Portal Light.

Checking the light to on in the OM and re-rendering will now show a much clearer andless splotchy render. gure 5.14

gure 5.14

Te light portal setting has efectively turnthis light source into a sort o directionalguide or the samples.

In my crap illustration belowgure 5.15 youcan see that without the Light Portal, the samples miss the mark and dont make it ithe scene. With the Light Portal activatedthe samples have assistance in their intenddirection .

gure 5.15

Te other solution is the Simple Light Porwhich ignores any lights/objects behind thportal and takes only the environment cointo consideration. Tis can speed up the

workow slightly.Light Portals can be helpul but are rarelyused in latest versions o Vray as the GI alrithm has become more rened. Tough isituations like this, they can be used to yoadvantage.


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Area Light - DomeTe Area light type - Dome is a similar to using a color or hdr eect as the Environment backgroundcolor, but uses direct sampling to provide a much more accurate result.

gure 5.16 (Environment rom VRay Settings)

gure 5.17 (Environment slot VRay Settings)

In gures 5.16 & 5.17 Ive loaded a *.hdr imageinto the texture slot o the Environmentbackground and have a standard GI setupready to render.

Te resulting render gure 5.18 has beenprocessed much like a standard luminancematerial. Light is being cast into the scenebut the sampling method is not direct.

While this is suitable or most tasks (espe-cially with an accompanying light setup), iyou want some extra bang or your buck, theArea light Dome is more powerul.

gure 5.18

gure 5.19

gure 5.16 (Environment tab rom VRay Settings)

gure 5.20

Controlling this light source is straight oward. Position o the light in your scene isirrelevant, however rotation values will athe orientation o an image based map.

A color/texture/material eect is loaded inthe slot (in this case ennis.hdr) and the result g5.20 is a directly sampled dome light.

Samples can be adjusted according.


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Area Light - MeshUsing a Mesh as a light source is one way to cast light rom geometry. Tough this efect does not difeand is easier to setup using Direct Illumination in a luminance channel.

gure 5.21

In the simple scene Vray_Mesh.c4d the lighton the upper le gure 5.21 is utilizing the VrayLight type - Mesh and has the cube objectloaded into the emptygeometry slotgure 5.22

gure 5.22

Te object on the right has a VRay materialwith a Luminance material applied and thedirect illumination option switched on.

gure 5.23

As you can see gure 5.23 theres no diferenthe two workows, other than ease o setu

A practical usage o this method is to cre-ate customized light shapes such as a curvplane or to match the shape and size o apre-existing light xture. Tough I wouldnrecommend lighting exclusively with thistechnique in mind, it can be perect to adthe nishing touches to an interior scene.

Prior to the creation o the Direct illumintion method in the luminance channel, it

was not possible to pick and chose workows. In the scene rom gure 5.24 Mesh ligwere used throughout the piece to light arthat needed to match the shape o the opeing.

gure 5.24 Inspire city


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Area Light - Remaining settingsWell take a brie at the remaining settings rom the Area light tab.

Aect Reections: With this option unchecked, the brightness o the light will be ignored by the materreectivity.

Invisible: All light sources are visible unless otherwise indicated. Unchecking this option will provide alight source, thought the origin o the light will not be visible.

No Decay: All lights in VRay have decay (allo) based on real world calculations. Enabling No Decaywill essentially create a light source with no allo at all. Tis is not recommended when trying to realically light a scene, but can be useul in product shots i you require an innite light source.

Double sided: A rectangular area light emits light rom the Z+ direction only, enabling Double Sidedenables the light to illuminate rom both surace normals. *CHECK

Samples: As discussed on Page 32, the amount o samples used determines the quality o the light sourLights producing undesirable noise benet rom additional samples.

Store with Irradiance map Using this option, the light calculated rom the Area map is processed andstored during the Irradiance map calculation. Discussed on Page 55.


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IES lightsIES data is taken rom existing real world lighting xtures and is made available or users in varyingproessions to download and utilize in their projects.

gure 5.25

An IES represents the shape o the lights all-of, but not the allof amount. In gure 5.25 its

easy to recognize the diferences in how eachlight reacts to the IES data.

Open example le IES_scene.c4d

Te rst thing youll notice in this scene iusing Cinema 4D version 12 or higher, isthat the visual reerence o the IES light isincorrectly oriented gure 5.26.

gure 5.26

Tis is the standard rotational value o thedeault light. o x it, rotate the p axis (the bluehandle) to -90. Note: Targets will always utilizethe P axis.

Omni is the light type indicated to use whworking with IES les. Creating a standar

light and enabling shadows, you can thenquickly move over the IES tab and load yodesired IES le.Open example le IES_scene2.c4d

gure 5.27

In this scene gure 5.27 the light is unchangeand retains the deault brightness as con-tained in the IES data. o increase brightnyou can enter a Lumens value or an increin intensity, this value would typically bequite high. Im going to increase to 10,000Enabling Sof shadows does as you would pect, it soens the shadow density, which occasionally desirable and only slightly mtime consuming to render.

A hint o color in the lter color will tintthe IES light to the desired value. Rarely alights 100% white, making a tint a worth-while change. gure 5.28

gure 5.28


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Final notes on lightingTe remaining light sources are Spot, Innite and Parallel. I wont cover these in detail because their prameters are logical and require no special attention.

In uture PDF instructional manuals well take a closer look at lighting individual scenes.

Lighting in VRay is a unique process, one that can be as simple as the Physical Sun/Sky setup or as complex as lighting a city. My advice is to stay away rom the simplest work ow and push the boundaries what can be done with lighting and composition.

Beore tackling a project that involves a lighting rig, try to think o the balance you want to strike beohand. In a night time shot or example - Would it be wise to create the overall environment light rst, letc and then work your way down to the lighting xtures?I would say not. My approach is to always stasmall, lighting xtures rst, achieve a sense o balance with the smaller details and when youve rened

and rened some more, only then would it be time to look towards the bigger lights.

Lighting can be a tedious part o the process i you make it so, continuously rendering the same shot tiand time again. Tis is why I recommend a base test setting, where the results o your scene lights canbe visualized in a matter o seconds vs waiting 10 minutes every time you make a change. Get used toswitching out between crap settings and medium ones to ensure you get overall sense or your scene anto ensure that with better settings, the lights will withstand scrutiny.

When you arrive to a point where the correct values ow, lighting is perhaps the most interesting parto the project, aer all this process is what brings your work to lie. It makes or breaks your work, so p

careul attention to what the masters do and try to replicate the best rigs without settling or mediocrit


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Chapter 6: Environment FogPrior to there being a working og solution in VRay, there were denite limitations when using the renengine or environment design and landscapes. Eventually ChaosGroup introduced the Environment which is a unique and physically accurate calculation o scene og. Te concept may seem quite limitinhow oen do I want og? Yet the implementation opens up a world o creativity.

Lets rst take a quick look at what it can do in terms o nished projects.

gure 6.1 Sunday gure 6.2 Fall gure 6.3 Modern og test

Te scene Sunday gure 6.1 is initially setup with only a physical sun/sky, but due to the Environment and the enabled Scatter GI parameter, the sun light is able to illuminate the og. Te result as in real lithat the og itsel becomes a source o illumination or the scene and the actual sun light and its potenshadow casting has diminished to such a degree that its almost completely invisible. An increase in ex

sure and an adequate interior lighting rig restores the balance.

Te scene Fall gure 6.2 is setup with Proxy objects and consists o around 2 billion polygons. Fog withscattering is enabled and is indicated to reach a height o 4 meters at a distance o 50 meters. Tis clearthe way or sun to still have a visible afect on the scene, but creates a sense o depth that would otherwnot be possible.

Te scene Modern og test gure 6.3 was the rst real test where I used the Environment og parameterGiven my lack o understanding at the time its easy to or me to critique the work. Te og height is essentially innite, which under such heavy og cover doesnt allow any light penetration rom the Sun.

Given an opportunity to re-work this piece, I would have chosen more tting parameters.

So lets do that, lets gure out what works best by creating a og lit scene.


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gure 6.4

Open example le Home_og.c4dHere gure 6.4 we have another typical Sun/Sky setup, pretty standard scene. Were goingto spice things up with a little og.

First, lets go to the editor camera and createa primitive cube gure 6.5.

gure 6.5

Manipulate the cube to extend the outsideo the building, without penetrating the thewindow & building layer gure 6.6. Were keep-ing the og strictly outside.

gure 6.5 - Cube has Xray eect or illustration only.

In the VRay settings rollout or Environmwere going to activate Environment Fog.

gure 6.6

I youd like to run a test render, youll seeresults are almost completely black.

Add the Cube object to the open slot orGizmos and add the Sun object to the opeslot or Lights.

Another render reveals a shot almost idencal to the original, minus the slightest hinhaze gure 6.7.

gure 6.7

Well want to check the Scatter GI box.

Tis tells VRay to look at the Fog as a vol-

ume and calculate its light solution based the density o that matter. Te scattering wboth illuminate the og and determine homuch light can escape the solution.

Another render would still resemble that the original.


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o nally see a result o using the Environ-ment Fog, well want to manipulate the FogDistance parameter, bringing that numericalvalue down rom 1000 to around 100.

Te change in distance aects the density,visible og at closer proximity is now thicker,

allowing less light to penetrate.

Your result may look slightly dierent thanmine gure 6.8 based on the exact shape oyour Gizmo geometry.

gure 6.8

Te Gizmo object(setting geometry as thefog) is the preerred workow as this givesus more control over the density o the og.Without a gizmo were using innite ogdepth and using the Fog height parameterwhich can be more difcult to control.

Sunlight is still able to penetrate the scene,but has become obscured by the og element.Subtle compensation with exposure or aninterior lighting rig would be the next step.

Its possible to use any shapes as a Gizmoobject no matter how irregular, allowing youto experiment with just about any geometryimaginable.

Its also possible to use as many light asrequired in order to scatter light through theog density.

In gure 6.9 Ive added two makeshi securlights outside the building and includedthose additions in the Environment og Lslot.

gure 6.9

You can see that this simple addition hadadded to the og illumination, which in tucasts more unique light into the scene.

A couple o interior lights to compliment outside, a little urniture, materiality and yhave an interesting setup. Certainly something outside o the boring Physical sky lo

gure 6.10

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