Hello, I am currently doing data conversion work, and there is a conversion error problem. The analysis reason may be the existence of Invalid polysurface in the original model. So how do I deal with this? How to operate rhino and how to implement opennurbs
Hi -
You didnāt categorize your post and thereās not enough information for anyone to be able to give a sensible reply. Iām moving this to āRhino Developerā for the time being but youāll have to provide files, code, and a well-formulated questionā¦
-wim
this is invalid polysurface
stationRoof1.zip (15.0 MB)
This is the first time Iāve ever seen a polysrf being joined without touching
Exploding and rejoining, makes a mess right away ā¦
Through further analysis, Iām seeing some render mesh issues:
Iām trying to improve the render mesh, but stuck in a long calculation
Yeah that calc took a while ( at least 30min ) and somem definitely weird here:
Thank you for taking so much time to help me analyze the problem. Iāve only recently started doing research, and Iām not very clear on commands and some definitions. So what is the main problem with the current model that causes invalid polysurface? render mesh? What instructions should I use to fix itļ¼
What is the cause of this problem
Iām not sure. Iād need to know what process derived these geometric entities.
Otherwise, Iād just have to try recreating them.
Iām not that familiar with āinvalid polysrfsā.
I imagine they were created with GH or something or some other software or formatā¦
These srfs seem to be all ātrimmedā, so Iāll try altering them with the following tool to see if I can fix them:
https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/refittrim.htm#(null)
Yeah that tool doesnāt seem to be advanced enough. 
Hereās an example of the problems I think are present in this āinvalidā geometry:
After I run āexplodeā, ārebuild edgesā, you can see how bad it really is:
Basically this geometry is āinvalidā because edges and vertices donāt line up. There might be other reasons, but this is what I see so far.
So, the best way to correct this would be at the source from which they were originally created because thereās so many of them ā as if they were created parametrically with Grasshopper or something.