How to change UV channel of loaded 3dsMax vrscene

[flat]

Question from my customer:

loading vrscene from 3dsMax into Houdini, but changing the "Channel Index" in the V-Ray UVWGenChannel applied to the object is not reflected in the rendering.
Which attribute does "Channel Index" correspond to?

Useing Houdini 18.0.391 + vray_adv_43001_houdini18.0.391_9c76421_6567

sample scene attached.

Sample.zip

[bdancer]

There are no UV channel indexes in Houdini, there are attribute names. Use "Channel (Named)" type.

[flat]

Thank you for the information.
Is there a way to convert or relink Channel Index to Channel Name?

[bdancer]

Except manually - no.
One object may have channel "map1" exported as 0 another as 1. That's why there is a "named" approach not related to index.

[flat]

Thanks for the advice.

My customers are researching how to use vrscene from 3dsMax in Houdini.
We hope some solution to match 3dsMax UV Index to Houdini UV Name.


Kind regards
-------
Yuji Yamauchi
OakCorp Support

[bdancer]

I'm still not sure what "use vrscene from 3dsMax" means.
Are they loading vrscene with VRayScene SOP? There shouldn't be issues in that case. You could send me a setup to check anyway.

[flat]

The .vrscene output from 3dsMax is imported by "Import Material" of VRayScene.
https://docs.chaosgroup.com/display/...-Ray+VRayScene

Materials automatically generated by this function are generated by UV Channel Index.

[chakarov]

Material is created with UV Channel index, because vrscene exported from 3dsmax contains geometries already saved with their UV Channel indexes. There is no way to force particular uv attribute to be exported as exact channel index in different geometries in Houdini.

[flat]

I understand that.
The main user of 3dsmax wants to reuse materials in Houdini.

Is it possible to add an option to output Index as "UV Name" to V-Ray Houdini's "UV Channel Index"?

[bdancer]

How we should predict which index should become which name?
If user just want to replace one node with another it could be scripted in Python.

[flat]

How we should predict which index should become which name?
If user just want to replace one node with another it could be scripted in Python.

don't want automatic conversion. User manually enters UV Name in Houdini for use.

I'm not familiar with Houdini's Python, but if the script can easily replace UV Index with UV Name, I'll tell the customer to try it out.

Thank you for your advice.

[bdancer]

Ok, I'll think of it.