Closed/complex polysurfaces not displaying as such

I’ve run into this a few times recently, where closed (or complex) polysurface doesn’t show up in a Ghosted/shaded viewport.

The isolines are present, just not the shading:


Rhino 7 SR14 2022-1-10 (Rhino 7, 7.14.22010.17001, Git hash:master @ d8a2d020be8cb487bfc091316ef32170cfc7eddb)

Windows 10.0.19044 SR0.0 or greater (Physical RAM: 32Gb)

Computer platform: DESKTOP

Standard graphics configuration.
Primary display and OpenGL: NVIDIA GeForce RTX 2080 Ti (NVidia) Memory: 11GB, Driver date: 10-26-2021 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 472.47
> Accelerated graphics device with 4 adapter port(s)
- Windows Main Display attached to adapter port #0
- Secondary monitor attached to adapter port #10

Hello- most likely, the outline has one or more self intersections - you can usually find these by turning on the curvarure graph ( CurvatureGraph command, at a low scale) and looking for the remaining spikes in the graph. Feel free to post the model too, I’ll have a look.

1 Like

ooh…good idea. I think you’re on to something.

If you ever think Pascal is wrong, you’re mistaken…


Your check is in the mail.



Classic. Solved the problem - thank you much Pascal!