UDIM and displacement not working correctly

[Bigguns]

when using UDIM displacement map, there is seam lines visible between the 2 UDIM maps.

I joined a scene and a render test to show you.

That's a major bug to me.

Let me know if it can be fixed soon

thank you

[Philip Shounev]

Hello,

Thank you for reporting this. After thorough investigation it turned out that the two UDIM textures have different amounts of white around the contact area which is the reason why there is a visible seam. It can be observed even without using VRayDisplacementMod - when a VRayLightMtl, wired to the composite texture, is applied to the sphere. However, there is a bug with keep continuity option when UDIMs are used and it has been logged in our bug tracking system under VMAX-8125.

Best regards,
Philip

[Bigguns]

Are you sure about that ? Because in older vray version it was rendering correctly. These maps are extracted from Zbrush and normally it works perfectly. try it with vray 3,5 instead and show me the result, I'm quite sure it will be ok. Because all my older project rendered just fine and since I upgraded to vray next it dont work, always a seams now.

[Bigguns]

It's not a map issue, Check this, with the displacement of max it's working 100 % ( and in Vray 3,5 this project was rendering perfectly ) but in vray next, something got broken into the displacement. Big nasty seams around UDIM. Tell me if it can be fixed soon please as I am on a project and I need the displacement to work with the UDIM. Test it on your side if you want, with an other project then mine, you will see it's not the map the problem.

[Philip Shounev]

I've made a few other tests and even with VRay 3.5 there is visible seam. I'm attaching a couple of screen shots made with Arnold renderer and VRay 3.5. Both images are rendered without displacement. If you'd like you can send the second scene for investigation, but when it comes to the first one - it seems to be an assets issue.

[Bigguns]

Can you give me your emIl i cabt send it here. Ill send to you in private.

Also , test it on your side with an other scene wich has udim and test it with displacemsnt on

[Philip Shounev]

You can send it over to support@chaosgroup.com

[Bigguns]

I sended the scene ! Let me know if Vray can be fixed soon thank you

[Philip Shounev]

The "keep continuity" option is now active for subdivision mode by default in V-Ray Next (it was greyed out in the previous V-Ray versions) so that seems to be the culprit for this particular scene. Since those textures are properly unwrapped and extracted from ZBrush, there's no need for this option to be active. Unchecking it should fix those visible seams.

[Bigguns]

YES !! it did fix it ! Why is this oiption on now ? I'm curious