• Civil 3D

Create a TIN surface and add breaklines

Create a TIN surface from survey data, and add breaklines to a surface.


00:03

One of two primary surface types offered by Civil 3D is the triangulated irregular network, or TIN,

00:10

which is constructed from a network of triangles,

00:13

providing a highly detailed and flexible representation of the terrain.

00:18

To create a TIN surface in 3D, begin with an open drawing that includes points from a survey.

00:24

This example also includes 3D feature lines, created from road center lines,

00:29

which will act as breaklines on the surface.

00:32

Breaklines force surface triangulation along the breakline,

00:36

preventing triangulation across the breakline.

00:40

To create a surface in Civil 3D, from the ribbon, Home tab, Create Ground Data panel,

00:46

expand Surfaces, and select Create Surface.

00:51

A Create Surface dialog appears.

00:54

To set the type of surface you wish to create, use the Type: drop-down.

00:59

In this example, the surface will be created from survey data,

01:03

so TIN surface is selected.

01:06

Next, enter a Name, such as “EG” for existing ground,

01:10

and then adjust the Description, Style, and Render Material as necessary.

01:17

Click OK.

01:19

In the Toolspace, Prospector tab,

01:23

expand the Surfaces folder to see that a new folder has been created for the EG surface.

01:28

Expand the folder, which contains Mass, Watersheds, and Definition.

01:34

Then, expand Definition to see all of the types of items that can be added to the surface.

01:40

Here, add a point group that was created previously to isolate the ground shots for the surface.

01:47

Right-click Point Groups and select Add.

01:51

In the Point Groups dialog, select the TOPO point group, and then click OK.

01:57

Immediately, the drawing updates with added contour lines.

02:02

However, you can see that the road centerline is not considered a breakline,

02:07

because the contours are continuing, rather than peaking, at this line.

02:12

You can fix this by adding a breakline.

02:15

In the Toolspace, Prospector tab, right-click Breaklines and select Add.

02:22

In the Add Breaklines dialog, enter a Description, such as “CLRoad” for the centerline of the road.

02:30

Expand the Type drop-down and select Standard,

02:33

because this type will enable triangulation right up to the breakline.

02:38

Click OK.

02:40

You are prompted to select an object in the drawing to set as a breakline.

02:45

Select one or more breaklines that you want to add,

02:48

and then press ENTER to complete the command.

02:52

Zoom in to the drawing, and notice that the centerline is now acting as a breakline,

02:57

with the contours visibly breaking at the line.

03:01

Now you can create a TIN surface from survey data and add breaklines to the surface.

Video transcript

00:03

One of two primary surface types offered by Civil 3D is the triangulated irregular network, or TIN,

00:10

which is constructed from a network of triangles,

00:13

providing a highly detailed and flexible representation of the terrain.

00:18

To create a TIN surface in 3D, begin with an open drawing that includes points from a survey.

00:24

This example also includes 3D feature lines, created from road center lines,

00:29

which will act as breaklines on the surface.

00:32

Breaklines force surface triangulation along the breakline,

00:36

preventing triangulation across the breakline.

00:40

To create a surface in Civil 3D, from the ribbon, Home tab, Create Ground Data panel,

00:46

expand Surfaces, and select Create Surface.

00:51

A Create Surface dialog appears.

00:54

To set the type of surface you wish to create, use the Type: drop-down.

00:59

In this example, the surface will be created from survey data,

01:03

so TIN surface is selected.

01:06

Next, enter a Name, such as “EG” for existing ground,

01:10

and then adjust the Description, Style, and Render Material as necessary.

01:17

Click OK.

01:19

In the Toolspace, Prospector tab,

01:23

expand the Surfaces folder to see that a new folder has been created for the EG surface.

01:28

Expand the folder, which contains Mass, Watersheds, and Definition.

01:34

Then, expand Definition to see all of the types of items that can be added to the surface.

01:40

Here, add a point group that was created previously to isolate the ground shots for the surface.

01:47

Right-click Point Groups and select Add.

01:51

In the Point Groups dialog, select the TOPO point group, and then click OK.

01:57

Immediately, the drawing updates with added contour lines.

02:02

However, you can see that the road centerline is not considered a breakline,

02:07

because the contours are continuing, rather than peaking, at this line.

02:12

You can fix this by adding a breakline.

02:15

In the Toolspace, Prospector tab, right-click Breaklines and select Add.

02:22

In the Add Breaklines dialog, enter a Description, such as “CLRoad” for the centerline of the road.

02:30

Expand the Type drop-down and select Standard,

02:33

because this type will enable triangulation right up to the breakline.

02:38

Click OK.

02:40

You are prompted to select an object in the drawing to set as a breakline.

02:45

Select one or more breaklines that you want to add,

02:48

and then press ENTER to complete the command.

02:52

Zoom in to the drawing, and notice that the centerline is now acting as a breakline,

02:57

with the contours visibly breaking at the line.

03:01

Now you can create a TIN surface from survey data and add breaklines to the surface.

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