Rhino 3D Mesh Not intersecting when export to AutoCAD

We currently have a 3D Mesh generated in Rhino out of surface, Which we need to import for Analysis in Structural software,

Analysis software only accepts Dwg format. We have tried exporting mesh in CAD Dwg format and found mesh lines not intersecting, even though it perfectly intersect in Native rhino format

Please Help,


Could you post the Rhino 3dm file, please?


Please find rhino 3dm file, perfectly intersect in Rhino. But no intersection found between curves in AutoCAD upon export to DWG

Wireframe_Intersection Issue In AutoCAD.3dm (221.8 KB)

Hi - I tested round-tripping the curves from Rhino to DWG and back into Rhino. They still intersect when they come into Rhino, so the problem must be in the other program that you are using - is the analysis software that you mentioned AutoCAD, or are you having problems in two other programs?

I don’t have AutoCAD to try on here - perhaps @mary has ideas on that.
I would look for tolerance settings in the receiving application and make sure that they are set to be the same as they are in Rhino. Your Rhino file is at 0.01, and if the receiving application is set at, e.g., 0.001, it is possible that it won’t find intersections.

Hi Naveen,
What are you using to test for the intersection of the spline curves in AutoCAD?
@wim opened the DWG in Rhino to test that geometry that was exported did intersect. That was a helpful test.

The AutoCAD Intersect command requires at least 2 solids, surfaces, or coplanar regions. It does not work on curves or splines.

What AutoCAD version are you using? And what command in AutoCAD are you using to test for curve intersection? Do you have a LISP file or something that you can share with me?

You can use the AutoCAD Intersection osnap to snap a end point of the line or other point, but it will only work on objects that intersect, are coplanar and their cplane is current.

Also the Apparent Intersection osnap will snap to the projected or “apparent” intersection to the current ucs, not the intersection in 3D space.

Please send more details about how you are testing for curve intersection in AutoCAD.

Mary Ann Fugier
McNeel Technical Support and Training
Seattle, WA