Unable to calculate area for a trimmed surf

See uploaded file that has a single trimmed surf from a larger polysurf that was generated from a subd. Was “Unable to calculate area” for the larger polysurf. Had to play a fun game of process of elimination to find the offending individual surface. Unable to calculate area for this small surf as well.

This has come up twice now for me with some polysurfs that subds are generating. I can extract, search and cleanly recreate the small surf, join it back, but this is tedious as hell on a large polysurf with hundreds or thousands of these mini surfaces.

Anyone have any ideas for why this is failing? Surf shows validno areacalc.3dm (108.6 KB)

I see that, thanks.
For now, UntrimBorder > KeepTrimObjects=Yes, then retrimming sorts it out.


@carvecream - see Greg’s comment below - do you have the original SubD object or one that shows the same problem?


How did that surface get made? Please show me how that was made. The trim curves are crossing and are outside of the surface domain.
If Rhino made this surface we need to figure out how and make sure it gets fixed.
Thanks for your help.

Hi Greg, I will try to upload this soon, will probably take me a couple of days to get to it though as I’m buried at work this week. But in a nutshell, that surf came from a subd made in v7, then tonurbs, etc.