In the file below, there are two polysurfaces that Rhino calls valid and closed. However, if I try to export them, I get this message:
Pressing F2 what I get is:
Command: _Export
Objects were skipped in export.
Breps: 0 written, 2 skipped
Layers: 1 written, 0 skipped
File successfully saved as C:\Users\xxxxx\Desktop\TestBrepExport.dwg.
Which doesn’t tell me much that I didn’t already know. And it says it was successful, even though it didn’t actually export anything, just a layer which is empty.
After exploding and rebuilding the edges on the objects, with a script (because this function is missing in Rhino) I tried selecting surfaces that have a very small area. Three showed up:
I deleted those and then joined all back up again, the right one joined into a closed polysurface again, the left one didn’t. The gap caused by the missing surface circled in blue was too big. I undeleted that one and then it joined up into a solid - crappy model, but will be OK for 3D printing. Both then did successfully export as DWG/Solids. I could have easily cleaned the left one up, but that was not the point right now.
NoDWGSolidExport.3dm (2.2 MB)
The question is, why does Rhino call these objects valid, yet one can’t export them as DWG?
Also, Rhino needs a native small surface area detection tool similar to how SelShortCrv works - call it say SelSmallSrf, based on area. The existing SelSmall command is based on the object’s bounding box, so it does not select these long, sliver surfaces. I need to rely on scripts for this purpose.