Using Terrain Model Elements

A terrain model is a set of triangles mathematically computed from point data collected on the surface being modeled. They are used to model highly irregular surfaces, particularly the surface of the earth. Terrain models are also referred to as digital terrain models (DTMs), triangulated irregular networks (TINs), or triangulated surfaces.

The Terrain Model tools allow you to import and label terrain contours and spots on terrain models. You can import a terrain model into a DGN to use its data. Terrain models imported from the LandXML file format are supported.

A terrain model is recognized as a MicroStation element type; when you select a terrain model, the Element Selection tool’s Element Type tab indicates that it is a "Terrain" element type.

Note: If a DGN file with a terrain model is created in MicroStation V8i(SELECTseries 3) and the DGN file is then opened in MicroStation V8i (SELECTseries 2) or later, the terrain model will not be visible. This is because the Terrain element type was not recognized prior to MicroStation V8i (SELECTseries 3). Although the terrain model will not be visible, there will be no data loss and the DGN file can be reopened in MicroStation V8i (SELECTseries 3), where the terrain model will again be visible.

Note: If a terrain model created in MicroStation V8i (SELECTseries 3) needs to be used in MicroStation V8i (SELECTseries 2) or later, then the terrain model can be dropped. When it is dropped the terrain model is removed and replaced by graphical elements, such as lines, shapes, and text.

Terrain Models and Element Templates

The display of terrain model properties can be controlled by using an element template. Once you have created an element template with the properties that you need, you can apply it to any terrain model.

Referencing Terrain Models

People in different job roles may want to see terrains displayed differently. For example, a designer of surfaces may need to see triangles, while a designer of drainage features may need to see contours. Rather than duplicating the terrain model in various places, the best workflow is to maintain a single terrain model and reference it into other DGN files.

When a DGN file containing a terrain model is referenced into another DGN file, you can allow the terrain model to be displayed differently in the other file. This allows the presentation to vary for different purposes, without changing the terrain model’s display in the original DGN file.