Help with patch for topography

Hi I’m trying to use the patch tool to create a topographic digital model, but it doesnt seem to do anything to my 2d drawing, I inserted this image and exploded it to access control points. I don’t know if the command simply isn’t working or if there’s something wrong with the curves

Hello - I’m not sure what you mean - did you run the Patch command? What input did you give it? Can you post the file?


Basically an input I found on a youtube tutorial

Here is the file,
much appreciated

patch topography.3dm (3.4 MB)

Hello - you have contour lines there but they are all co-planar so a patch through there will result in a plane. You’ll need 3d data…


Well there’s one non-planar point. But LOTS of duplicate elements.

I don’t understand what you guys mean by co-planar and non-planar, I uploaded this topographic map from autocad as a pdf, how can I edit it to make it 3D ?

Also the white lines I made because I thought I had to close the curves

What do you mean by non-planar point and duplicate elements ? I inserted this file as a pdf originally a dwg from autocad

I’m not @pascal, but I can answer some of your questions. For patch to create a 3D surface, the information you give it (points and curves) must also be 3D. In your file, all curves are on the same plane. That means in the XYZ coordinate system, their Z’s are all 0. So you have to manually move each curve up or down and then the patch command will work like you want it.

Duplicate elements means that there are two curves that are the exact same size and are located in the exact same place. This can cause problems with any Rhino command. You have many duplicates because converting from PDF to DWG doesn’t work perfectly. You fix this problem by running the command “seldup” and then pressing the delete key. I would recommend exploding the drawing first, with the “Explode” command, then do “seldup”, delete the duplicates and then rejoin the curves. Then, manually move them up or down by however much is the height difference, then patch surface. Hope that helps, if you have any other questions you can keep asking.

Edit: Also, the curves don’t have to be closed for patch to work. So you don’t need the white lines.

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That really cleared things up, I was having trouble understanding the technical language, I get it now I get what you mean and I’m fixing the file up. I’ll keep posting if something else comes up

Thanks alot man !