Hi
i unwrap a polysrf and everything seems fine unless i rotate the object. If i do this the texture behaves in a strange way as seen on this image.
It’s not the first project where i found this problem: everything works all right til the moment i rotate the object
Any idea? Thanks
p.d. i’m running Rhino 7 SR16 2022-3-8 (Rhino 7, 7.16.22067.13001)
If i open UV editor it seems to be alright
but when i click OK it gets wrong again
I don’t know what happens only I ask me how your both states are looking if you render the view. (Is rendering your goal?)
So far I understand Rhino is using an idealized mapping for display use but for rendering a limited polygon based mapping is used. So, maybe you see the display pipeline switching between idealized projection and polygon mesh UV mode.
Thanks for answering!
Once i apply the UV editor glitches appear as seen on the first image (it was an on going render).
The strangest issue is that the mapping works perfect till the moment i rotate the object for visualization purposes.
In this kind of projects i need to make the renders for product viz but also all the technical for fabrication. I tried to mesh the polysrf but didn’t work .
Hope somebody at McNeel could help
The rendering looks perfect before you turn the object or the viewport preview?
There is a pitfall - also if the mapping looks perfect at the viewport you can get distorted mappings during rendering. So, you never can trust the clean looking mapping of the viewport. Workaround - use a finer display mesh or use a V-Ray mapping like tri-planar (it should follow the turned object if you convert an object to a block).
Here it was discussed.
1000 thanks!! (i knew your avatar looked familiar, from Chaosgroup forum!)
My steps are:
After reading your links It seems more a limitation of Rhino than a bug.
Tri planar is not and option since i need to control texture mapping because of my clients, we ussually work with wood and stone.
Anyway, thanks a lot!!
Sounds like a bug. Maybe internal a kind of custom mapping object is be used and this isn’t following the visible, rotated object.
I would try a workaround and convert the object to a block first, switch to block edit mode, apply a custom per UV editor and leave the block editor mode. My hope is that the mapping is fixed within the block.
Maybe @nathanletwory can check the issue and tell more. 
Hi @nachetz
This is a known issue and we are actively working on improving this in Rhino 8.
It would be great to have your model as a test case - you can use our upload page if you don’t want to share it in public here.
Here is a workaround that sometimes solves this issue:
When your model still renders correctly (before rotating it) run _TestRenderMeshMapping. That command makes the custom mapping primitive match the object render mesh and resets mapping transformations. Then it is less likely that the next rotation will ruin the rendering.
Thanks @Micha ! you were right, it worked! block + custom UV. I had no more problems!
Thanks @Jussi_Aaltonen .
I’ll upload the file through the link you told me.
I tried _TestRenderMeshMapping and it got worse:
@Micha technique worked great, at least on this project!
