roeland wrote:milanm wrote:In V2 we could use boundary interpolation to eliminate distortion on UVs but in V3 none of the options make any difference.
Same distortion can also be reproduced in Cinema 4D if the method for subdividing UVs is set to 'Standard' instead of 'Boundary' or 'Edge'.
Regards
Milan
I think the issue is the topology of the UV coordinates.
→ In OpenSubdiv 2.x it doesn't make a difference whether or not the UV's are duplicated accross polygons, or if there is one value referenced by more than one polygon.
→ OpenSubdiv 3 treats UV coordinates in the same way as vertices, so in the first case (duplicated UVs) OpenSubdiv treats it as a discontinuity and you get distortion.
For instance, the attached file contains 2 tessellated planes, and the one with duplicated UV coordinates shows the distortion:
BoundaryInterpolation.orbx
--
Roeland
Thanks Roeland, this helped me find where's the problem.
I did a bit of research and I discovered that ALL UVs are like that by default in Cinema 4D!
Further more, as far as I know, there is NO way to weld UV vertices in C4D!
When I imported the two obj plane files from your example I got the same issue with UVs on both of them.
At first I couldn't tell the difference, but after checking them out in a different 3d app I realized where's the problem..
Also, it's definitely not obj/FBX import issue because new geometry modeled and UV mapped in C4D also has the same issues.
I guess dealing with this in OctaneC4D plugin would slow down geometry updates, so the only way out for C4D users would be for Octane to support unstiched / unwelded / duplicated UVs. Without that, I'm afraid this feature would be useless for C4D users
Let me know if I can help in any way.
Thanks again.
Edit: ..Some references:
http://www.c4dcafe.com/ipb/forums/topic/85284-weld-uv-points/#comment-583189http://forums.cgsociety.org/showthread.php?p=5698826#post5698826Regards
Milan