CompuServe Messages

If you want to do something that's free, try this (I use it all the time). Assuming you have a polyline for each contour line, and each polyline is up in space at the proper elevation in AutoCAD space (i.e. 0', 5', 10', etc.). Run the 3D Surfaces command, use the Rulesurf command, and pick two adjacent 3D polylines. This will create a 3D mesh object connecting the two polylines. The Surftab 1 and Surftab 2 variables control the resolution of the resulting mesh. I use a value of 2 for the up/down the slope value, and anything else for the cross-slope value. Set this value as high as you want to ensure a more accurate mesh file. Pick each pair of polylines in the same order as you move up or down the slope. This technique breaks down a little if you have really curvy contours, in which case the faces tend to overlap around corners. If you do this on a given layer such as Surface01, then turn off the other layers and DXF this layer out. If you have any questions, drop me a line… Regards, Gary