Problem with VRay Proxy and Variation Texture

[Danielhruby]

I have a problem where the Variation texture mo longer applies properly to separate mesh islands (the pebbles) in my mesh item. All works fine with Vray material until I convert to a Vray Proxy. The variation texture is still affecting the mesh, but only with the initial color value at 0% on the graph. On a side note, changing the mode of the VT to Item applies the VT in large chunks of multiple mesh islands. As seen in images 4 & 5, the two items of pebbles are not being colored differently as you might expect. and instead are using some other sort of tag to define them as "independent "items". So, in this case, where I have another heavy 3d gravel scene to render (almost 500 MB! gravel mesh), the VRAY Proxy system can not be used.

Is there are similar method using VRay Textures to control this situation? Hopefully this is just a bug.

[vladimir.nedev]

Yes, the Variation Texture in "Mesh Part" mode does not work with the V-Ray Proxy. It's a special case that's not implemented.
The V-Ray Proxy splits the geometry in voxels based on proximity, so the connectivity information is lost, so instead it has to be baked in the .vrmesh file when creating it.
And this is not implemented.
The only work around for now is not to use the V-Ray Proxy in this case.

As for the "Item" mode, if you have different material/part/selection tags on those pebbles, it's normal that they get a different color.
That's what Modo does as well, the "Item' mode generates different random numbers for different materials on the same mesh.

Greetings,
Vladimir Nedev

[Danielhruby]

Seems like it would be a good problem to fix. My gravel is a good example, but an even better use case is for objects like trees and shrubs where using variation texture can really help add some random coloration to trees. Trees of course are perfect candidates for Proxy Item class. As fort the groups in images 4&5, it turns out the the original mesh was assembled with multiple groups of gravel and the resulting consolidate mesh had multiple part names assigned to the small squares of pebbles. So, that all happened prior to VRay Proxy conversions and are not related tot his issue. The main issue is that I really need to have proxy items be able to use the Variation Texture and affect disconnected Polygon islands so that I can randomly modulate color/tone of leaves/pebbles AND Be able to off load all of that hi poly Geo into a format like a Proxy. Thanks for the answers though. I will try to work around it some way else.

[vladimir.nedev]

I have it logged for fixing, and yes, it was requested by other people as well.

There is no other workaround.
Although for 500K polygons, using V-Ray Proxy is not really needed.
It's a common misconception that if you want to instance something you have to use a V-Ray Proxy, but that's not true.
If you instance or replicate that 500K pebble mesh, V-Ray will store only one copy of it, no need to offload it to V-Ray Proxy in order to instance it many times.
Same with trees and shrubs.

Now, if you add many other unique meshes, offloading to .vrmesh can help with loading speed of the .lxo file and interactivity in Modo's OpenGL viewport.

Greetings,
Vladimir Nedev

[Danielhruby]

Thank you Vlad. It was a 500mb gravel mesh, not 500k in polys. The point was to offload that 500mb out of my scene for faster performance. The variation texture works fine on normal meshes, but break when converting the mesh to a proxy. It seems to me, that there should be no situation where converting to a proxy should break your materials. I could use a few pebbles and replicator, but unfortunately, the pebbles will self-collide and not look convincing.

Still, I am very excited with Vray for modo. I?ll be buying a license this week! Thank you for your fast responses!

[Bart247]

If you Load an alembic file instead of a vrmesh, would the same issue occur? I guess if the proxy loader is splitting either vrmesh or alembic into voxels, the connectivity is lost in both cases. But maybe it treats alembic meshes differently?

[vladimir.nedev]

If you Load an alembic file instead of a vrmesh, would the same issue occur? I guess if the proxy loader is splitting either vrmesh or alembic into voxels, the connectivity is lost in both cases. But maybe it treats alembic meshes differently?

The Alembic files are not split into voxels, I think.
So, yes, it should, in theory, be easier to make this case work.
But it's not implemented at the moment.

Greetings,
Vladimir Nedev