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How to create a mesh or surface from contour lines


nestly

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I have little to no experience with 3D terrains, but I'd like to be able to create a surface or mesh from contour lines to give a better 3D representation of terrain than just contour lines. "Drape" seems to be the tool ACA, but I'm wondering if AutoCAD can do something similar. LOFT sorta works, but even then, I have to do it in sections, and I'm not really looking for a solid.

Contour test.dwg

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Thanks Cad64, I had already tried a another terrain model app (albeit freeware) that claims to do similar.... all I got was error messages from that one. http://www.cadstudio.cz/en/apps/dtm/

 

I was really hoping for a solution using just AutoCAD. I lofted only the top 3 contours (making them a solid) then used CONVTOMESH. It took about a minute to turn it into a mesh, and the file size ballooned to 17.2 MB. If I did all the elevations in the little sample drawing I posted, I imagine the filesize would be completely untenable. I wonder if meshes are typically that large, or maybe the process I used is just that inefficient?

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Try the DRAPE command.

 

Yeah, that was the first thing I tried, but I don't think that tool is available in vanilla AutoCAD.

 

Unknown command "DRAPE". Press F1 for help.

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Thanks JoeTony, I may have to download and try that. I really like the cross section tool, I currently spend way too much time manually creating sections.

Edited by nestly
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I installed the trial, and it works fairly well. So far I haven't been able to achieve the level of smoothness I was hoping for, but I'll continue to play with it.

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I figured out that the 3D surface isn't really a surface, it's a bunch of flat faces in a block, so the transitions are necessarily sharp/abrupt. The polylines in my sample drawing are optimized because that's new construction, but when I did the whole site including all the existing contour polylines that have thousands of vertices each, the model gets pretty heavy to zoom/pan/orbit. Still, it's pretty cool software, but I'm hoping to find some clever user that wrote a lisp to create an actual surface from contours.

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