(Resolved) Can't figure out Multi ID Texture

[charles_breach]

Hey guys,

I'm trying to randomly apply multiple textures to books I scattered with copy to points, randomly rotated with a for each loop, and unpacked. I followed this thread: https://forums.chaosgroup.com/forum/...98#post1071698 and tried using Multi ID Texture to try and add different diffuse textures to each individual book with the sampler node and random_by_polyshell.

It seems to work, except I can only get at most 2 textures to show on the books out of the 4 I'm testing with. Ideally, I'd have 20 different textures for the diffuse and bump of the material, to create a wide variety of books. Any help trying to make this happen would be greatly appreciated.

I'm using V-Ray Core, 5.00.50 and Houdini 18.5.351

[Gosho.Genchev]

Hey charles_breach ,

unpacking the geometry will cause V-Ray to treat all the books as a single mesh, thus none of the "random_by" options on the Sampler will give you what you're looking for - a single value per book.
The easiest thing to do would be to add a float attribute on the packed primitives, before unpacking them, and set it to e.g. rand(@ptnum).
You can then use this attribute in material network, pass it through a V-Ray Random VOP and plug that into the Multi ID texture.

I've attached an example scene here: https://drive.google.com/file/d/15Id...ew?usp=sharing

PS: Performance-wise it would be better to keep the books as packed primitives - the VRScenes would be smaller in case you're planning to render on the farm, and the time to first pixel will be lower too because V-Ray will only need to write out the unique geometry and the instance points instead of the entire scene.

Hope that helps!

[charles_breach]

That did it! Thank you for helping me with something so basic. The example scene helped a lot. Hopefully, there are other beginners like myself out there who'll find this helpful!

cheers.

[Gosho.Genchev]

Glad I could help.

There's also an example scene for more complicated workflows where you want to target a particular named primitive on the documentation page for the Pattern ID texture: https://docs.chaosgroup.com/display/...Ray+Pattern+ID

Best regards!