Is Vray textures scaling possible from GH?

Rendering V-Ray
1

Dear experts,

Is there a simple way to scale the texture mapping in Vray directly from GH? (e.g. from .vrmat files)

Thanks!

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It seems that in other softwares like 3dmax,maya, we can use shading nodes to change the material,including the texture.It’s similar to the component system in GH.
But it seems that we can only change texture in traditional panel of vray.—At least no plugin for vray can be found in GH after installing vrayforrhino…

But I’m not sure too.

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Hi everyone

to answer it short - yes, in more than one way.

long answer:
There is object-space mapping and texture-space mapping. The final result in the renderer is the multiplication of both matrices

In V-Ray for Grasshopper, since Update 2 you can control both of them
You can use the V-Ray Bitmap component to alter the texture-space mapping:
image
More info: https://docs.chaosgroup.com/display/VNFR/V-Ray+Bitmap

For object-space mapping, V-Ray now reads all Rhino mapping channels if the object being mapped is a referenced Rhino object, or you can use plugins like https://www.food4rhino.com/app/human to generate custom in-grasshopper object mapping.

2 Likes
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Hi Nikolay,

thank you for your post. I am currently also having some problems with texture mapping in rhino/grasshopper which maybe you can help me with. You mentioned that …“V-Ray now reads all Rhino mapping channels if the object being mapped is a referenced Rhino object…” how ever when I reference a rhino object in grasshopper it losses the rhino mapping. Am I doing something wrong? example.gh (7.4 KB) example.3dm (1.1 MB)

example
example1102Ă—468 24.4 KB
example gh
example gh800Ă—450 226 KB
example rhino
example rhino800Ă—450 232 KB

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Hi @antonio_mauricio

You’re correct. For that case it doesn’t work.
It took me some time to find out the problem, but finally cracked it.

It turned out that the RhinoCommon API skips one of the texture coordinate components if the mapping widget rotation matrix is not WCS. This is only a problem for compound objects like polysurfaces. Exploding the object into individual surfaces is a kind of workaround

This will be fixed in the next update

Thank you

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Hi Nikolay,

that you very much for your reply. Exploding the polysurface did not work for me. What did work was exploding the polysurface and then untrimming the surface but it’s no really a work around because I don’t get to render the actual geometry I want. I guess this is part of the same issue you described on the RhinoCommon API? Should this also get fixed for the next update.

Is there any ETA for when the next update is coming out? As a Rhino / Vray user I thought it would be quite handy to be able to do animations in grasshopper but if it will still be a while until these issues get fixed I might need to find another tool for the job in the meantime.

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Hi Antonio,

the next update 2.2 will be available around the end of April or beginning of May.
I noticed that trimming fixes the things even if you join the geometry back to polysurf, but I agree, that is not a desired workaround.

V-Ray for Grasshopper already provides quite a number of animation tools, and a new expansion is coming with the next update. I’m interested in what more does your workflow require in terms of features. We are planning a few more things in that area, and I’ll be glad if you share what’s on your mind.

Thank you