Building the 3D model and generating contour levels

In this exercise you will generate the 3D terrain model using points with x, y and z coordinates or polylines with a certain elevation (breaklines). The interpolation method used is triangulation with linear interpolation.
For more information about this function and available options please see the Help file.
1. To complete this exercise open 5_3DModel.dwg from Example folder in TopoLT installation path (by default it is C:\Program Files\TopoLT\Examples). In this example, the 3D model will be generated from points and from polylines with a certain elevation.

2. Set the plan scale 1:1000 from Program Options » Plan.
3. Draw points with Coordinates » Draw Points command or type rappct in the command line. Click Choose File button and select 5_3Dmodel.coo from the same folder as the drawing (by default C:\Program Files\TopoLT\Example).



4. To set the display mode go to Program Options » 3D Model. Before you start to draw please set the interpolation method, colors, dimensions and contour level intervals.


5. Go to 3D Model » Build 3D Model or type m3d in the command line.
In the command line you receive the following messages:
Select points Select/All <All>: you are asked to select all points in the drawing or just a number of them. For this example, select All » Enter.
Delete points with elevation <0.000>: to eliminate points with a certain elevation or to clean the drawing of points with 0.00 elevation (default value is 0.00).
Select lines or polylines of forced change of the slope (breaking lines)… select the two blue polylines in the drawing.
Select 3D model boundary / <ENTER> without boundary… The 3D model can be limited by selecting a a polyline defining the area where you want the 3D model created. When you do not want this polyline press Enter.
A new window is displayed where you can view the 3D model a make renderings. You can choose the projection method (ortho or perspective), light intensity, texture quality, smooth rendering, textures.

After reviewing the 3D model press OK. The 3D surface is created. Please note how the two breaking lines made the surface to change slope.


6. After the surface is created, next step is to create the contour levels. Go to 3D Model » Draw Contour Levels or type cnn in the command line. Select the surface and the contour levels area generated according to the settings from Program Options.


7. One of the 3D model editing functions is Trim 3D Model. The 3D model can be trimmed in order to reduce its size or to create a hole in the surface. Trimming can be useful in some cases when you want to calculate volumes.
Go to 3D Model » Trim 3D Model or type trimm3d in the command line:
Select 3D model…: click the terrain surface;
Select cutting limit…: select the polyline marked 3D model limit (1);
Pick on the side that will be cut: click on the outside of the limit to trim the exterior side of the surface.