Create Terrain from Existing Points and Contours

Looking for an easy way to use your survey data to create terrain models in the desired form, like a Civil 3D Surface or a TIN Mesh? With Plex-Earth, you can use the topography data handed to you from your survey team, either as elevation points or contour lines, to create surface models in your drawing.

Before You Start

• Your drawing must be georeferenced so the output terrain aligns with real-world coordinates.

• Ensure that the points and contour polylines in the drawing are accurate and correctly positioned.

• The feature accepts:

  • Points (with elevation data)

  • Polyline contours (closed or open, with elevation data)

Step 1. Terrain from Objects Command

Go to the Plex-Earth ribbon → Contextual Data panel → Create Terrain dropdown button → Terrain: From Objects.

Alternatively, type in PXV_TERRAIN_FROMOBJECTS in the command line.

Step 2. Select the Base Drawing Objects

After starting the command, Plex-Earth prompts you to select the objects (usually in the command line) that will define the terrain surface.

You will be asked to provide the following object types:

• Points
  Elevation points used for surface creation.

• Breaklines
  Contour polylines or lines that define terrain features and guide the triangulation of the surface.

• Boundary
  A polyline or line that defines the outer boundary of the terrain surface.

• Holes
  A polyline or line outlining an area that should be excluded from the terrain surface.

Points and/or Breaklines are required, since they contain the elevation information used to generate the terrain. Boundary and Holes are optional, but they can help control the shape and limits of the terrain model.

Select the objects for each prompt and press Enter to proceed. If you do not want to define an optional category (Boundary or Holes), simply press Enter to skip it.

Step 3. Create Terrain from Points or Contours

You can create terrain using either survey points, contour lines, or a combination of both.

Terrain from Points

If your drawing contains elevation points:

1. Select the points when prompted for Points.

   

2. Press Enter to skip Breaklines if no contour lines are available.

3. Optionally define a Boundary polyline to limit the surface extent.

4. Define Holes only if certain areas should be excluded from the surface.

Terrain from Contour Lines

If your drawing contains contour polylines:

• Press Enter to skip Points, if there isn't any.

• Select the contour polylines when prompted for Breaklines.

  

  📢 Tip: In case you catch a polyline or point you don't need, you can remove it from the selection by clicking on it while pressing the Shift key on your keyboard.

• Optionally select a Boundary polyline to control the terrain extents.

• Define Holes if needed to exclude areas from the surface.

Step 4. Generate and Insert the Terrain Surface

After selecting the required objects, Plex-Earth generates the terrain surface based on the elevation information from the selected points and/or contour lines.

Once the terrain model is created, it can be customized further and used for other tools such as terrain analysis, snap objects, draping, etc. You can also insert it into the drawing as static CAD objects such as contour polylines, a mesh, elevation points block, or a Civil 3D surface, depending on your workflow.

Here is an inserted mesh as an example:

FAQs