Displacement issues with UDIMS

[kremiansky]

I've generated some maps from a scan in zbrush, and the negative values weren't working on 32 bit. Adding negative colors, tweaking all the displacement shift/alpha shift in the file loader didn't help.
After a while I decided to use 16 bit maps, and voila now I have another problem- on the uv seam there's tearing. The displacement doesn't have sharp transition, there's enable continuity enabled, the texturing filter is both off on the file loader and in the shape node with vray displacement control. The texture is defined as raw and using two zbrush format udims. Am I missing something?

[Morbid Angel]

32 bit displacement should work out of the box. Did you set the displacement bounds to manual and specify the positive / negative value? For the seam, see if turning off filtering in file node helps.

[kremiansky]

Thanks for the reply! so here you can see I am assigning the 32 bit map to the surface, and as you've said- it's working out of the box without any displacement shift. The tear is still there, but when I change it to udims- also the negative values stop working. Setting filter to none didn't change anything sadly.

[kremiansky]

I even unchecked subdivide uv's as the maps were generated without subdividing uv's and I know there was some subtle difference between zbrush'es subdivision and maya's.

[Morbid Angel]

you need to do this:
bounds to explicit and set neg value to -1 or more

[damaggio]

Aside from Dmitry's note you can check this one I made from Vlados's comment on the forum,although this one is for vector displacements.

[kremiansky]

So:
Angel and gooseneck thank you! Explicit bounds works with udims and 32 bit, which is nice, but there's still tearing, and it looks the same both with continuity off and on. Sure Zbrush is known for shenanigans with maps, but what would cause holes instead of simply stretched polygons?

[Morbid Angel]

can you post this scene with the displ tiles for us to check?

[yolov]

Can you try if enabling 'keep continuity' helps in any way? Also - what V-Ray version is this?

[kremiansky]

Whoops sorry didn't reply for such a long time, didn't see any notifications. this is vray 3.6 and keep continuity wasn't making any difference. If I remember correctly did blur a line on the 16bit texture between those udims in mudbox and it helped a bit, but still there were some artifacts. I'll take another look at it later once I can and post it here. Thanks everyone :P

[chaosseed]

Whoops sorry didn't reply for such a long time, didn't see any notifications. this is vray 3.6 and keep continuity wasn't making any difference. If I remember correctly did blur a line on the 16bit texture between those udims in mudbox and it helped a bit, but still there were some artifacts. I'll take another look at it later once I can and post it here. Thanks everyone :P

Hi
Would you use PTEX?
https://docs.chaosgroup.com/display/...es+from+Mudbox
MAYA also uses the same.
Or UV SEAM is not visible on the camera.

[kremiansky]

Hi
Would you use PTEX?
https://docs.chaosgroup.com/display/...es+from+Mudbox
MAYA also uses the same.
Or UV SEAM is not visible on the camera.

I'll have to use that asset soon enough, I'll check that, and all the previous suggestions, thank you very much!