Exercise 3: Adding a Hide Boundary

In this exercise, you will create a hide boundary on the surface, which will mask unwanted triangulation.

A boundary can be created from any polygon or polyline, but in this exercise you will use an existing breakline.

This exercise continues from Exercise 2: Deleting TIN Lines.

Add a hide boundary

1. Open Surface-4C.dwg, which is located in the tutorials drawings folder.
   Note:

   This drawing is similar to Surface-3.dwg with the addition of the C-TOPO-BRKL layer, which displays breaklines.

2. In Toolspace, on the Prospector tab, under the Surfaces collection, expand the XGND surface.
3. Under the XGND surface, expand the Definition collection. Right-click Boundaries. Click Add.
4. In the Add Boundaries dialog box, specify the following parameters:
   • Name: XGND-Pond Hide
   • Type: Hide
   • Non-Destructive Breakline: Selected
   • Mid-Ordinate Distance: 1.0000
5. Click OK.
6. In the drawing, select the polyline object that matches the perimeter of the pond.

   The polyline that matches the pond perimeter

   
7. Press Enter.

   The hide boundary is added to the surface definition. The surface displayed in the drawing is modified to display the pond as a ‘hole’ in the surface.

   How the surface should appear with the hide boundary

   

To continue this tutorial, go to Exercise 4: Smoothing a Surface.