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Tutorial:
Import Export DXF

To quickly use the program to convert a DXF file containing contours into a DXF file containing surfaces describing the terrain, proceed as follows.

Start

• Start SimuTerra.

Import data

• Choose File > Import DXF....

• Select the file named "SimuTerra sample input 1.dxf", and click the Open button.

A dialog will display progress, then results. Note that no points were created, only polys, and that there was an average of about ten vertices per poly. This information is not important in this simple case, but can sometimes be very useful. Dismiss this dialog by clicking on the OK button.

The data (polys, in this case) in the file should now appear in the window, and all be selected (with handles appearing at each poly vertex). (You could instead import the file SimuTerra sample input 2.dxf; same idea, different terrain.)

Create a DTM

• Choose DTM > Create DTM.

(If the command is not available, click in the window, then choose Edit > Select All to select all objects again.) The selected objects will be used to create a DTM. You should see contour lines. (If the DXF file which you've imported consists of edges from a SketchUp foam core model, choose the appropriate DTM-creation command from the DTM menu.)

Export DXF

• Choose File > Export DXF....

A dialog will appear, DXF Export Entity Options. Choose only one of the items. The first one, "Triangles as polyface mesh", may be the simplest. Click the OK button.

• Give the file a name, and indicate where to place it. In most cases you will want the file name to end with the default dxf suffix. Click the Save button.

The file should now be ready for import into another program which reads DXF. (Each line is terminated with a carriage return, which is standard on the Macintosh.) The suffix assigned to the file name is “dxf” by default; you could change the suffix for an individual file if you need to.

• Use a 3D modeling or CAD program to open the file which you exported. (Some programs don’t understand polyface mesh, while some don't understand 3DFACE; you may have to try both.). You can import into SketchUp; after doing so, you typically have to choose Camera > Zoom Extents in order to bring it into view.

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