( open ) [ HOU-2563 ] Attribute like Cd don't render time subdivide as they should.

[benfox]

Using the production build of Vray 5.00.50 for Houdini 18.5.408 point attributes aren't being interpolated correctly when using render-time subdivision.
The test is creating a box, adding a color SOP set to bounding box and then enable render time subdivision and assign a material which uses the Cd attribute.
Mantra does this and interpolates the color smoothly with render time subdivision.
Vray seems to apply the attributes to each subdivided face.

[chakarov]

Hi benfox , can't reproduce it with latest nightly build. What is your V-ray build number? Can you share the scene ?

[david.anastacio]

Hi benfox , can't reproduce it with latest nightly build. What is your V-ray build number? Can you share the scene ?

Hi chakarov,

I can confirm that this issue exists, I also bumped into into (slipped through with all the work). I attached a test scene and this also happens in VFH 4.3.

This happens when using opensub divs, the point data is incorrectly interpolated. This however does not happen when using "Render as Subdivision" in the displacement properties, but we never use displacement subdivisions due to their lack of performance when compared to the open sub div.


No open subdiv applied:

With open subdiv applied:


Best,
David.

[chakarov]

Now I reproduced and reported it.

[benfox]

Thanks for the speedy responses, great to see you are all on the case! I am using the VRay production build of 5.00.50 for 18.5.408