Problem using VRayVertexColor in MeshLight texture material

[thomashl]

I have a piece of geometry I want to use as a meshlight, and I want the color of the light to be driven by a vertex attribute with the VRayVertexColor node. I am not having any luck. When I render the geometry as a regular mesh, I can use the vertex attribute just fine. Do meshlights not support vertex colors?

[ivaylo.ivanov]

It really seems broken. A work-around is to assign the same VRayVertexColor to the material.

[thomashl]

Not sure what that means, exactly. Do you mean that I should apply a material to the mesh as if it were a regular surface and that once I make it a mesh light, it will use that material for the color of the light?

[ivaylo.ivanov]

The work around is to assign a regular material with the same texture. It doesn't matter when you do this step.

[thomashl]

It still doesn't seem to be working.

I definitely checked that the geometry has the attribute; I did a render of it as a standard mesh with the VRayVertexColor connected to the illumColor and my colors attributes rendered as expected.

If I then select that geometry and select the "Create -> VRay -> Mesh LIghts -> Turn Selection Into Lights", and render again, my render shows up white.

Is there something else I need to do?

[ivaylo.ivanov]

Let me double check and attach a scene.
Are you using 3.1? I think this work-around doesn't work for 3.0. If you have access to the 3.15 nightlies, it's fixed already there and we will start building stable 3.1 nightlies very soon to fix such issues.

PS: here is the scene
meshlight_vertexcolor.zip

[thomashl]

No, we are currently using 3.0, so we will install 3.1 and I will try the workaround in that version.

Also, I am confused by your post when you say you "will start building stable 3.1 nightlies". Do you mean a stable 3.2?

[t.petrov]

No, he means exactly 3.1.
The idea is that we'll apply some fixes (which we think are important and safe) from the main development branch to the 3.1 branch.
When this happens a new stable 3.1 nightly build will be available.

[thomashl]

Hi there,

Has this fix been merged into the latest version of 3.1? I'm trying to test it and the version of 3.1 we have installed still doesn't have it.

[ivaylo.ivanov]

The fix is in the 3.15 nightly builds. But the 3.1 stable branch is not online yet.

[thomashl]

Hello,

Any further development on this? I would like to use this feature in a stable branch. Is it available yet in 3.1?

Our current VRay3.1 version is:

[2015/Nov/2|16:22:27] V-Ray: V-Ray for Maya version 3.10.01 from Jul 18 2015, 07:07:05
[2015/Nov/2|16:22:27] V-Ray: V-Ray core version is 3.25.01

[ivaylo.ivanov]

yes, it's fixed in 3.1

[thomashl]

Can you confirm the date on the version of 3.1 that has the fix? Our version, dated "3.10.01 from Jul 18 2015, 07:07:05" is not working. Is there a later version?

[tashko.zashev]

Can you confirm the date on the version of 3.1 that has the fix? Our version, dated "3.10.01 from Jul 18 2015, 07:07:05" is not working. Is there a later version?

Hi Thomashl,

In order to get fixed build for this issue you will need access to the Stable nightly builds (who are also numbered 3.1). The one you have installed 3.10.01 from Jul 18 2015 is the latest official release. You can send access request to support@chaosgroup.com