The current terrain is used by a number of different 3D tools that require a terrain upon which to generate/place a 3D turn simulation. The current terrain concept allows you to perform various operations repeatedly without having to continuously re-select the terrain element.

It is important to remember that only one terrain can be current at any one time, and it can be any supported surface or mesh element:

AutoCAD/BricsCAD/ZWCAD:

• Polygon Mesh
• Polyface Mesh
• Civil 3D Surface
• Civil Terrain object (BricsCAD v20)
• MicroStation ORD Terrains
• 3D Face (three vertices)

Note: Set the MESHTYPE system variable to 0 in versions 2010 or later of AutoCAD and version 13 or later of BricsCAD to create compatible polygon or polyface surface elements.

MicroStation:

Mesh

Note:

• Use Mesh from Points or Mesh from Contours instead of Mesh from Element when creating meshes for use with AutoTURN Pro.
• MicroStation terrain elements are only supported in MicroStation V8i SS3.

Both AutoCAD and MicroStation:

• TORUS Grading Model
• NEXUS Grading Model

The current terrain is the last selected surface or mesh element. The current terrain is set by using the Select Terrain tool. If a terrain has not yet been selected when a 3D tool requires one, you will be prompted to select a terrain at that time. The selected terrain becomes the current terrain and will be used for subsequent 3D tools until the Select Terrain tool is used again to select a different terrain.

These functions act on the current terrain:

• Generate 3D Arc Path
• Place 3D Simulation
• Convert 2D to 3D