Business and Computing Deanery Multimedia Week 20 Lighting

Business and Computing Deanery

Multimedia

Week 20 Lighting

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Last week Animation Cameras Video

Streaming Compression Production

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This week Realtime and photorealistic Rendering Lighting concepts Types of lighting Shadows

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Realtime v. photorealistic Compare lighting

OpenGL - max 8 Photorealistic – 10 per character

Convergence of realtime and photorealistic Realtime is now used to plan real

movies Used extensively in games

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Internalor3rd party

Traditional

The CG production pipelineStory

Art

Set design Layout Animation Shading

Modelling

Rendering

Lighting Simulation Effects

Film

Commercial

Editorial

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Rendering The act of translating the information in

the files that make up the shot into a single frame of film

Rendering "fills in" geometry with color, shadow, lighting effects, etc.

Pixar have created Renderman 10 years ago it took 6 hours to render one

frame How many today?

Use render farms

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Concepts Light has warmth (yellowish) or

coolness (bluish) Intensity Angle if incidence Radiosity

Light reflecting from an object Attenuation

Light becomes weaker with distance3ds max v7

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Lighting basics Three main sources of lighting in

classic photography Key Fill Backlight

Concepts apply to 3D programs, plus Ambient light

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Getting it right

3ds max v7

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Key light Outdoors

The sun Indoors

Major window Main electric light Flash on a camera Spot light on a stage

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Fill and key lights Fills in the dark shadows

cast by the key light Outdoors may be created

artificially Indoors from secondary

lights Distant window Light fitting

Softens shadows 3ds max v7

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Backlight Situated behind the subject Separates the foreground from the

background Can make the scene more three-

dimensional

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Lighting strategies

3ds max v7

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Planning lighting Default lighting Use this until you are happy with the

scene, then add lights Use as few as possible Start with the key light

Maybe a spot Add fill

Use omni or several spots Finally add accent lighting

3ds max v7

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Ambient light Not a light source

Light from other sources bouncing of walls, the ceiling and other objects in the scene

3ds max v7

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Types of lighting Standard

Spotlights Omnidirectional light Directional light

Advanced Photometric lights

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Spotlights Casts a focused beam of light like a

flashlight, a follow spot in a theatre, or a car headlight

3ds max v7

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Omnidirectional light Known as omni light Like a bare light bulb Casts rays in all directions from a

single source

3ds max v7

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Directional light Also known as Distant lights Cast parallel light rays Primarily used to simulate sunlight

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Target lights Concept like cameras Target

Easier to aim Simply position the target object at

the centre of interest Free

3ds max v7

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Lighting directionSingle light from side Single light straight on

Both sides Reduced full fill

3ds max v7

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Activity Open up your model of a room, save

with a new file namse Add one or more spotlights to

provide lighting and render the scene Experiment with moving them around

and rendering the effect Add an omni light behind the scene Alter the values to achieve a

balanced rendering

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Standard light settings Intensity Angle of incidence Attenuation Reflected light and ambient light Colour

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Attenuation Natural reduction

of light intensity

3ds max v7

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Brightness and colour Intensity sets the brightness of the

scene Range from 0 to 255 (white) Colour – use the RGB sliders

3ds max v7

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Activity With your scene experiment with

your light settings Vary the light settings for:

Intensity Angle of incidence Attenuation Reflected light and ambient light Colour

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Use of shadows

Default lighting

Spot plus low level back lighting

Spot

3ds max v7

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Shadows Photometric and standard lights

both have the same options for generating shadows

Two types Shadow mapped Ray-traced

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Shadow mapped Grayscaled texture map based on the

lighting and mesh Soft-edged More natural May be blocky May be inaccurate May be incorrectly positioned Do not take transparency into account Do not take on the colour cast of the

object May use a lot of RAM 3ds max v7

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Ray traced shadows Ray tracing

techniques Have a hard edge

Software can be used to soften

Very accurate and precise

Does not use a lot of RAM 3ds max v7

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Hotspot and falloff Hotspot

Angle of the inner portion of the beam

Falloff Angle of the outer

beam Differences in

angles make the effect softer

3ds max v7

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Include and exclude Some software allows you to set up

lights that affect only certain objects Use a pick list to select objects

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Colour and mood Cool colours – blues and violets

Still and calm Warm colours – yellows, red and

orange Fiery and energetic Intense and active

Be careful, keep it subtle

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Activity Create a flat surface with a sphere

and a cone sitting on top Add a spot light Add a fill light

Alter the hotspot/fallout Alter the type of shadow

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Photometric lights Photometric lights

enable you to more accurately define lights as they would be in the real world using ray tracing

Distribution, intensity, colour temperature can be set 3ds max v7

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Global Illumination with Radiosity Standard lights are simpler than

natural lighting Using photometric lights with a

radiosity solution with your lights provides a better model of the real world

Radiosity is rendering technology that realistically simulates the way in which light interacts in an environment

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Preset photometric lights Generic 60W Bulb Generic 75W Bulb Generic 100W Bulb Generic Halogen Spotlight Generic Recessed 75W Lamp (web) Generic Recessed 75W Wallwash (web) Generic Recessed 250W Wallwash (web) Generic 4ft Pendant Fluorescent (web) Generic 4ft Cove Fluorescent (web) Generic Street 400W Lamp (web) Generic Stadium 100W Lamp (web)

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Photometric lights Target Point

Similar to a standard omni light, emits light from a geometric point

Spotlight Focused beam

Web distribution Distribution of light Many lighting manufacturers provide

web files that model their products 3ds max v7

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Sunlight and Daylight A system that follows the

geographically correct angle and movement of the sun over the earth at a given location

You can choose Location Date and time Compass orientation.

3ds max v7

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Daylight Daylight combines sunlight and

skylight The sunlight component can be either IES Sun light

Illuminating Engineering Society Values set automatically based on geographic

location, time, and date Or a standard light (a target direct light).

The sky component can be either an IES Sky light Or a Skylight.

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Self assessment You have been asked to model a

lecture theatre for Hope Compare and contrast the lighting

required for A guest lecture without note taking A lecture with note taking and

discussion sessions

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For Next Week Submit your Portfolio 2.2 Work on the 3ds max tutorials Directed reading chapter 6 and 10

Giambruno M, (2002) 3D Graphics & Animation, 2nd Edition

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References Giambruno M, (2002) 3D Graphics & Animation,

2nd Edition, New Riders, ISBN: 0-7357-1243-3 Kerlow I. V., (2003) The Art of 3-D Computer

Animation and Effects , 3rd Edition, John Wiley & Sons Inc; ISBN: 0471430366

Murdock K.L., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: 0764579711

Screen shots taken from 3ds max 7 User Reference