civil 3d surface

Civil Surface Base Plan: Tips and Tricks Matt Kolberg – Cansel

CI5187 In this class you will learn a workflow and tips for developing an efficient and working

base plan for an AutoCAD® Civil 3D® project. We will discuss parcels, points, figures, and surfaces. The class will also provide tips and tricks for styles, connecting the dots, symbology, and surface creation and editing.

Learning Objectives At the end of this class, you will be able to:

Create accurate surface models efficiently

Create existing linework from survey data effectively and quickly, with and without the use of the survey database

Apply symbology to survey data, based on point descriptions, with and without the use of description keys

Use styles to make the linework and symbol creation process smooth and pain-free

About the Speaker Matt is currently the ATC Manager for Cansel, an Autodesk Value Added Reseller in Canada.

His primary responsibilities are all things Civil 3D, including network installation,

implementation, support, training, and customization. Prior to his time with Cansel, he worked

as a drafter/designer with a Civil Engineering consultant for 12 years. With this consultant, his

main tasks were drafting production and design work using Civil 3D and Land Desktop prior to

that. His alternate tasks were IT related; setting up new users on the network, hardware

troubleshooting, and leading AutoCAD and Civil 3d training for internal staff.

[email protected]

Civil Surface Base Plan: Tips and Tricks

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Table of Contents

Parcels ...............................................................................................3

Site Geometry ........................................................................................................................ 3

Subdividing Your Styles .......................................................................................................... 4

Drawing Management ............................................................................................................ 5

Points ................................................................................................6

Styles ..................................................................................................................................... 6

Symbols – Description Keys ................................................................................................... 7

Symbols – No Description Keys.............................................................................................. 8

Drawing Management ...........................................................................................................10

Figures ............................................................................................. 12

Connecting the Dots - Survey Database ................................................................................12

Editing Survey Figures ..........................................................................................................13

Connecting the Dots - No Survey Database ..........................................................................14


Surfaces ........................................................................................... 16

Point Group ...........................................................................................................................16

LiDAR and Scans ..................................................................................................................17

Breaklines .............................................................................................................................17



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Parcels On a Land Development project, the existing property to be subdivided will be an integral part of

your base plan. The existing parcels don’t take up much of your project’s overall bandwidth.

Still, there are a few techniques you can employ to make Civil 3D (and thus your project

manager) happy.

Site Geometry The lines and curves that form your existing parcels must be defined well. Many times parcel data is obtained

from a municipality’s GIS plan. Each parcel is its own closed loop. This is undesired behavior as it can

compromise the integrity of the Civil 3D Site.

Dana Probert, the Civil 3D Technical Marketing Manager, created a document a few years back which

describes in very good detail this requirement in addition to other “rules” of the trade. The document is several

years old, but most of the text still applies today.

http://civil3drocks.blogspot.com/2006/06/parcel-rules-explained.html

Geometry that crosses, or overlaps other geometry can be difficult to see and fix with traditional AutoCAD

tools like trim, break etc. Luckily Civil 3D comes with most of the Map 3D tools. The one in particular is called

Drawing Cleanup. The command is MAPCLEAN. Below are all of the cleanup options available. The ones

used often in this situation are (in the following order); Break Crossing Objects, and Delete Duplicates. The

resulting geometry can now be used for parcel definition.

If after following the rules above, you still have a drawing that is somewhat unstable or there are still some

weird things happening, you have another option. There are four commands that help fix Site problems. They

are undocumented in the Help file, but they are explained in the Autodesk knowledge base. Go to

www.autodesk.com and in its search bar enter “Undocumented commands to resolve specific Site issues with

overlapping objects”. The first document you will find should explain the following commands;

AeccFindSiteOverlaps, AeccRemoveDupFeatureLines, AeccRemoveAlignmentsFromSite,

AeccRemoveDupLotLines.

http://civil3drocks.blogspot.com/2006/06/parcel-rules-explained.html

http://www.autodesk.com/


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Subdividing Your Styles A subdivision often begins with a single parcel. The land developer may have purchased several, but you’ll

generally start with the combination of those.

When you create a Parcel from Objects in Civil 3D, that parcel, and its geometry, are placed in a Site. As you

subdivide, the styles you choose get applied. Maybe there are a few different parcels styles within your

subdivision. Finally, you’d like the very outer boundary to use a given style, in this case the style is red.

It’s very simple; your site has a style setting which controls the outer-most boundary of all of your parcels.

Change the style for the Parcels collection and ensure that style is at the top of the hierarchy, and voila!


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Drawing Management Parcels are one of the objects that can’t be Data Referenced. Whether this is a good idea or not is not the

point of this paragraph; we can’t do it, so how can we deal with it? Like many other things AutoCAD, there

can be a multitude of opinions on this one; here’s my take on it.

I prefer to have a single drawing that contains all of my existing

and proposed parcels. I will XREF that into all of my plan and

profile sheets. This method is probably used by many of you

already, but the problem isn’t how to get the parcels into your

plot sheets, it’s how to label them efficiently. Here we have an

alignment that is DREF’d in with the parcel labels within an

XREF. The alignment cuts through the parcel labels. Since

they are within an XREF, we can’t move them. What to do?

Any object in Civil 3D that can be labeled, can be labeled

through an XREF.

1. In my Parcels base file, I will use a label style that

does not plot.

2. In your plot sheet, simply use the Add Area label

tool and select those grey (no plot) labels within the

XREF. New labels will be added to your current

file. The labels can be moved at will.

3. What’s more, when the parcels in your parcel base file change, and the XREF is reloaded, the labels

will update.

There are a few rules you must follow to get this to work properly.

1. Whn attaching the XREF, a scale of 1 MUST be used.

2. When attaching the XREF, a rotation of 0 MUST be used.

3. When attaching the XREF, the insertion point MUST be 0,0,0.

4. If any of the above three rules are broken, you will get this error.

5. Feel free to Unload the XREF; when it is reloaded, the labels will return.

6. DO NOT detach the XREF, your labels will be deleted!


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Points Points are the first objects you deal with in pretty much every project with the exception of

LiDAR and other point data derived by scanning. Knowing how to deal with them properly will

save you time and frustration.

Styles Symbology

Points can’t display without assigning a style to them. Most points are displayed with an X. Some points are

displayed with a symbol such as a manhole, a catch basin, or a valve. While the size of the X is often

unimportant; many times these are turned off when the drawing is plotted, symbol size can be quite important.

There are two typical ideals for point display; those that are pictorial, and those that are real. Pictorial symbols

do not attempt to represent the actual size of the object they are symbolizing. Real symbols are there to

accurately show the size of the object. For example, a manhole symbol man consist of a simple circle. This

circle is not the actual diameter of the manhole, it is purely symbolic. It appears the same size on drawings

regardless of the drawing scale. In the example below-left, the manhole is show plotted at two different

scales. It appears the same size, 3.mm.

This “annotative” behavior solves many drafting problems, but it isn’t always desired. For symbols like

manholes and catch basins, it is a good thing, but when the symbol is meant to represent the actual size of the

object, this is not good. In the example above-right, the tree canopy is critical. It is 2m in model space and

scales accordingly with the viewport scale.

These behaviors are accomplished within the Point Style, Markers tab. The manhole style’s size option is

“Use drawing scale”, the tree’s size option is “Use size in absolute units”.


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Symbols – Description Keys Points are typically used for three tasks; creating surface data, connecting linework, and showing symbols;

manholes, trees, signs etc. Adding symbols to your drawing is done in two ways; manually, or through the use

of Civil 3D Description Keys which apply symbols automatically based on the surveyor’s codes.

There is one very important prerequisite to using description keys; you as the Civil 3D technician and your

surveyor MUST agree on a standard set of survey codes and your surveyor MUST use them in the field. If

this prerequisite is not met, there is no hope of automating this process.

Description keys are used for several things:

Point styles

Label styles

Applying layers

Full descriptions

Scaling the symbol

Rotating the symbol

I’ll outline Point Styles in this tutorial.

Create a Point style

1. In the Settings tab, under Point, right click Point Styles and select New.

2. In the Marker tab, choose the symbol type “Use AutoCAD BLOCK…”

3. Also in the Marker tab, specify the size. Close the dialog, you’re done.

Create the Description Key

1. In the Settings tab, under Point, right click Description Key Sets and select New.

2. Right click your new Set and select Edit keys…

3. Under the Code column, enter the surveyor’s code. E.g. MH (manhole), CB (catch basin) etc. Note,

these are case sensitive. If you use “cb” and the surveyor uses “CB”, it will not match.

4. Keep in mind you can use wildcards in the Code column. My surveyor codes trees in the following

manner: “tr 500 oak”. 500 is the diameter, oak is the type. If my description key read only “tr”, I

would not get a symbol. My description key code needs to be “tr*”. The asterisk matches anything

after “tr”.

5. Assign the desired point style. Close the window, you’re done.

What you’ve just done will apply the symbol to new points added to the drawing. It will not affect any points

that were already in the drawing before you created this description key. To do this, simply right click the “_All

Points” point group (or any other point group, or any number of selected points in the drawing) and select

Apply Description Keys.


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Symbols – No Description Keys If you’re not using description keys, in the absence of a third party application, you need to insert blocks

manually. This method has the obvious weakness of taking far more time, but there is another weakness that

is potentially more dangerous than time…omissions. What if you miss a block or two? It’s not that hard to do

if there are hundreds of blocks to insert. Imagine there’s a telephone pole onsite, but there’s no block on your

plan that shows it. If it’s supposed to be removed for a road, and there aren’t provisions for it in your design,

there will be a problem.

So we need a way to make this manual process faster and we need to take steps to avoid these possible

omissions. We still need to insert the blocks manually, but the following tips will highlight the points involved

so it is very obvious where they are in the DWG.

“The Blue Style”

1. Determine which point description you are dealing with. CB’s, MH’s, Tree’s etc.

2. Create a Point Group named “Blue”. Include all points with the above descriptor.

3. Create a Point Style named “Blue”. Use the circle custom marker, set the size option to absolute

units, set the size to something rather large. For my drawing 20m is adequate.

4. Apply that “Blue” Point Style to the “Blue” Point Group.

5. In the Point Group properties, Overrides tab, set the Style override to the “Blue” Point Style. This is

to override any possible description keys, or manual style settings that have been applied.


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6. You’ll end up with this.

7. You can now use the Insert command to insert your blocks. It’s very easy to see where they should

be placed.

“Isolate This”

1. Make a selection of the desired points. Here are two methods:

a. In the Prospector’s Item View, sort by Description, highlight the points, right click and

choose Select.

b. Make a Point Group that contains the desired points, in the Prospector, right click that group

and choose Select.

2. Your points will be selected in your drawing window, in the drawing window with the points selected,

right click and choose Isolate Selected Objects.

All objects in the drawing will disappear leaving only the selected points visible. Insert your blocks onto these

points. This technique is preferred than simply Isolating the layer because layer isolation in Civil 3D is not

reliable due to possible nested layers within styles.

When you’re finished inserting your blocks, you’ll need to turn off Object Isolation.

3. On the bottom-right of the AutoCAD window, click the Object Isolation button and select End Object

Isolation.


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Drawing Management Sharing

Civil 3D’s Data Shortcut technology does not allow for sharing point data between drawings. There are

sharing techniques if you use Vault, however, or the Survey database. Both methods have their advantages

and disadvantages. Many times, a consultant is not interested in employing either method. So what can be

done?

Let’s begin with our ultimate goal; what are some reasons we want to share points between drawings?

Points need to be shown using different styles in different drawings.

Points need to be turned off and on for varying reasons. Simple layers within an XREF will not

suffice.

Point properties change in one drawing and we want to push these changes out to other drawing that

“share” these points.

The easiest method is to just copy points between drawings, or reinsert them. This does not come without

consequence.

If you have a surface that is using those points, there could be problems depending on how the point group

was defined.

If you have moved or rotated point labels and they are reinserted, those edits will vanish.

My technique is far from foolproof, but it does help solve some issues.

1. Open the drawing and edit the points as required.

2. Export those points to a new text file. (Right click a point

group and choose “Export”).

3. Open the second file (the one you need to update).

4. Use the Import Points from File tool. Just reimport the

points like you did in the beginning.

5. Select the file and import as usual.

6. You will receive this dialog box warning of duplicate point

numbers. Use the Merge option. Close the dialog.

Any point label edits you made prior to this will be retained. Any

surfaces, once rebuilt, will be updated.


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Osnap

Drawing lines and snapping to points using the can sometimes yield unexpected results. Many drafters like

their linework to be 2-dimensional; they want nothing but 0 elevation for all lines. Connecting lines between

points can result in 3D lines. There are two methods to allow for 2D lines

1. Point Style: edit a point style and in the 3D Geometry tab, change the following…

2. Set the following system variables.

OSNAPZ = 1

ELEVATION = 0

Be careful, however. OSNAPZ will ALWAYS revert to 0 when you open drawings. Make a point to set its

value when you’re ready to draw lines, or create a LISP routine to change its value every time a drawing is

opened.

User-Defined Properties

Your surveyor may pick up pipe inverts inside manholes. Showing these

inverts in your point labels will help you create your existing pipe networks

easier. User-defined properties can be employed to facilitate adding the

inverts to your point labels.

Here is an AU class from a couple of years back which outlines how.

http://au.autodesk.com/?nd=class&session_id=3108

Here is a link to the Civil 3D tutorial.

http://docs.autodesk.com/CIV3D/2012/ENU/filesCTU/GUID-6F9EFF4C-4D8F-478B-A246-3FCC3B14230-

25.htm

http://au.autodesk.com/?nd=class&session_id=3108

http://docs.autodesk.com/CIV3D/2012/ENU/filesCTU/GUID-6F9EFF4C-4D8F-478B-A246-3FCC3B14230-25.htm

http://docs.autodesk.com/CIV3D/2012/ENU/filesCTU/GUID-6F9EFF4C-4D8F-478B-A246-3FCC3B14230-25.htm


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Figures Getting Civil 3D to connect linework (in Civil 3D they are referred to as Figures) for you can be

very easy, but there has to be somewhat of a symbiotic relationship between your surveyor and

you, the CAD professional. In addition to this relationship, one, or both of you may be required

to adjust your workflow.

Connecting the Dots - Survey Database Once that relationship has been established, there are some ideal prerequisites.

1. A Figure Prefix Database should be created.

2. You need to agree on a set of survey codes and USE THEM.

3. The survey needs to be done with linework connectivity on mind; connectivity codes should be used

in the field.

A Figure Prefix Database defines things like which styles to use for which lines, whether those lines are

breaklines, and, arguably the most critical, which lines are drawn when specific survey codes are used. You

see, if you set up the database correctly, the surveyor may not ever have to change his workflow. Honestly,

he still will, but this will make it far easier for him to swallow. Here’s how…

1. In the Survey Toolspace, right click and select New.

2. Click the plus to add new entries and assign values to the columns accordingly.

3. Name: this is the code that the surveyor will use. These are prefixes; the “*” wildcard is implied. For

example, the surveyor can use “EP1”, “EP-R”, “EPL” and the code will trigger linework.

4. Breakline: when figures are drawn, there will be an attribute applied to each line with “Yes” specified

here. This allows for very easy addition to surfaces later. If you want to connect Culvert points, for

example, make sure you DO NOT specify these as Breaklines.

5. Lot Line: if this is set to “Yes”, Civil 3D will draw Parcel Segments, not Figures. Parcels can be

made from them.

6. Layer: fairly obvious.

7. Style: again, fairly obvious.

8. Site: specify which Site on which the Figure will be placed.


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Editing Survey Figures With the workflow specified above, any time points are inserted into the survey database that have codes

that match those in the Figure Prefix Database, Survey Figures will be drawn. In the case above, all CL

and EP points will be connected with lines. It’s very likely that you don’t want ALL of those points to be

connected however. In the image below, we do not want a segment in the area shown.

To accomplish this, the point description needs to be changed; you need to add the appropriate linework

code. You will find the list of available linework codes in the Linework Code Set in the Survey Toolspace.

The code we need to use here is “fnc b”; short for

begin. It’s important which point is edited. That survey

figure was drawn from left to right, so to “Begin” a new

figure, we edit the description of point 5503.

Alternatively, point 5502 could have been changed to

“fnc e” (for end). Only one “b”, or “e” is required, not

both.

In the next example, let’s assume we DO NOT wish to connect point 5503. The Figure should be drawn

from 5502 to 5504. Essentially we need to remove that vertex. We all know how to do that with a

polyline, but how to do it with a Survey figure? The “Delete PI” tool can be used, but this will not affect the

Survey Database, only the DWG file. Instead, right click the Figure and select “Edit Survey Figure

Properties”. Select the desired point and click the delete vertex button. This will affect BOTH the DWG

and the Survey Database.


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Connecting the Dots - No Survey Database After a survey is done and you’ve imported your points, the next logical step is to create linework, connecting

edge of pavement, ditches, fences etc. In the case you’re not using the survey database, this is a somewhat

manual process, but there are some techniques to make it more efficient. In any case, you start with the

POLYLINE command and your OSNAP set to NODE. You can just connect them all manually, or…

Transparent commands

When the polyline command asks you to pick a point, use the above

tool in the Transparent commands toolbar, “Point Number”, or type

‘PN. You will be prompted to type in a point number, then another,

and so on. Or you can type in a range of numbers, “34,40-52, 97”.

The preceding string will connect points 34, then 40 through 52, and

finally 97.

This makes quick work of connecting the dots, but its main limitation

is that your point numbers need to be sequential. The points to the

right are not well suited to using this technique.

“The Blue Style”

Just like “The Blue Style” used in this manual for highlighting points, the same technique can be used to

highlight the points required for connecting the dots. Refer to “The Blue Style” on page 8 under the Symbols

section of this manual for details.

Once the points have been highlighted, set your OSNAP to “Node” and use the polyline command to connect

the points.

“Isolate This”

Again, the same technique used in the Points section can be employed here to draw your lines. For details,

refer to “Isolate This” on page 9.

It will be very easy to connect those points once they have been isolated. Don’t forget to unisolate them once

you’re done.


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Drawing Management So now you have your lines drawn. There are some things you can expect to have to deal with. If you used

basic polylines, there is not much more for you to manage. If you allowed Civil 3D to connect the dots for you,

using Feature Lines, there are other issues you need to be aware of.

Linetypes

Feature lines are 3 dimensional objects. Very useful for many things. Like 3d Polylines, linetypes are

generated along their 3D lengths. There will be more dashes and spaces the steeper the line is. Below

shows a 2D line (top) and a steep 3D line (bottom). The left elevation is 0m and the right is 100m.

There’s nothing that can really be done in this circumstance,; you just need to be aware of the behavior.

Personally, I have rarely had such a steep feature line that it made an obviously visible difference, but it can

happen.

OSNAP

Since feature lines are 3 dimensional objects, they will return 3D lengths when using object snaps to measure

distances. Often designers need to measure 2D lengths between feature lines. In the image above, the lines

are 2m apart when viewed from the top, but when I measure the perpendicular distance between them I get

varying results depending where I pick. Like with Points, you can use OSNAPZ to override the elevations to

give you the 2D distance between them. Refer to “OSNAPZ” on page 11 in the Points section for details.


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Surfaces An accurate surface is essential to your design. If you don’t have confidence in your existing

ground, how can you have confidence in your design? A poorly modeled TIN can skew your

earthworks volumes and even be the cause of an improper property acquisition design. Take

the time to ensure you have a quality surface.

Point Group If you are in possession of a typical set of survey points, most of those points are required for your surface, but

there are possibly dozens that are not; monuments, iron pins, stakes, etc. Any point that is not actually on the

ground will create havoc for your surface. Imagine a surveyor that shoots the nut on top of fire hydrants. This

is clearly a problem for a ground model.

Let’s begin with a good practice of naming your Point Groups as you receive them. When I import a file a

surveyor has given me I always use this naming convention:

Date Surveyor’s-Name File-Name e.g. “2011-09-19 Matt K points.nez”. I know pretty much everything I need

to know about those points for future reference simply by reading its name.

1. Next you need to define the group, or groups, that will define your surface.

Make a new Point Group called “Surface”.

2. You need to define which points belong in this group. In the “Point Groups” tab, you can specify

which points from other groups will be included in this new group.

3. Lastly, in the “Exclude” tab, enter the raw descriptions of the points that do not belong in your

surface. You can specify as many as you need here as long as they’re separated by commas. Feel

free to use wildcard as well. Here I am using the asterisk to exclude any points with raw descriptions

that begin with “culv” or “mon”.

4. You now have a point group that is ready for surface creation.


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LiDAR and Scans The first rule when using LiDAR or Scan data is NEVER to import Cogo Points. 500,000 points or more is not

uncommon with this type of data. Civil 3D will slow to a crawl (or stop responding) if you try to import these

points. The good thing is, you don’t have to. There are three reasons to use point data; insert symbology,

create linework, create a surface. You need point descriptions in order to insert symbols and create linework;

scan data is just Northing, Easting, and Elevation information, no descriptions, so it’s impossible to know

where to draw your lines. For creating a surface, there’s another way to get that point data into your surface

as long as your file is compatible with one of Civil 3D’s Point File Formats (NEZ, ENZ etc).

1. Create your surface.

2. Browse to add your point file(s) in the Point Files section of

your surface definition. That’s it! Easy.

3. Keep in mind, this file is linked to your surface. If you remove

it and rebuild, you will receive an error. On the other hand, if

your provider gives you a revised file, overwrite the original

file (use the same name) and rebuild the surface. The

revised points will be used from that new file.

4. If you need to use a new file, or you need to move the original file, you can point the surface to the

alternate file in the Surface Properties, Definition tab by clicking the file button.

Breaklines Breaklines are essential for creating an accurate surface given a typical ground survey. With scan data, there

is so much data that Breaklines often are not required.

If you’re using auto-generated survey figures using the survey database, your job is easy. Just add them from

the survey database.

A typical rule is “breaklines must not cross”. Usually this is true, but sometimes crossing breaklines is ok as

long as both lines share the same elevation where they cross. If you do have breaklines that cross, you will

get an error in the Event Viewer. You can use the Zoom to function to inspect the crossing and see if anything

needs to be done.


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If you need to resolve crossing breakline problems…

1. Start the “Resolve Crossing Breaklines” tool found in the Modify Surfaces ribbon.

2. You’ll see a list of all crossing breaklines. Select any and click Zoom To. The

breaklines in question will be highlighted; red is the lower breakline, blue is the

higher.

3. Inspect the elevation difference and decide which resolution option you need and click Resolve. Or

select Trim or Gap.

4. Rebuild the surface. The Prospector may not indicate that a rebuild is necessary. Trust me, it is.

Drawing Management Keeping your project files efficient and speedy is what we all need. Two techniques that will help you with this

goal involve how your Civil objects within files are organized and how you can more easily visualize your

surface if it is very large.

If you require a profile to be created in a file other than that where the surface resides, you have only one

choice; Data Shortcuts. If all you need is to see some contours and label them, you can choose either Data

Shortcuts or XREF’s

Data Shortcuts

Reference the surface via Civil 3D’s Data Shortcut tools in the Prospector then just label the contours as you

normally would.

XREF’s

Alternatively, XREF the file which contains the surface. Then simply label it as you normally would. Like for

Parcels, you MUST observe the following characteristics for this to be possible.

The XREF scale must be 1.

The insertion point must be 0,0.


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The rotation must be 0.

What are the advantages of either method? With Data Shortcuts you can sample profiles, sample sections,

and change the surface style. This cannot be done with an XREF. XREF’s, however, are more familiar to

many people and may cause less confusion. Given the choice, most Civil 3D users would just go for Data

Shortcuts for their added functionality. But if you’re looking for an alternative, you can employ XREF’s in

certain situations.

Viewing Large Surfaces

If your surface a very large number of points, viewing it in the Object

Viewer, or simply zooming in and out can cause significant delays in your

workflow, or worse, can cause stability issues. There is a feature named

“Level of Detail” (LOD). Turning this feature on will limit the displayed

detail when zoomed out and bring back that detail when zoomed in.

In the following example, the Surface style is set to quite a high contour interval. At this zoom level, with LOD

off, the contours and TIN lines are just mashed together. When LOD is on, we see only some of the contours.

When zoomed into the centre portion, all of the detail returns. The advantage here is pure performance.

Zooming is faster. Trying to view a 2 million point surface in the Object Viewer was problematic. With LOD

on, it makes this possible.

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