(Fixed) [HOU-3814] export shader with a map from houdini to 3dmax give scrambled UV on fur

[anais_martin]

Hello,

Not sure it's the correct place to post this, but here's my problem.
As said in the title, I'm currently having an issue while exporting a .vrscene of a material with a map plugged into it.
Our current pipeline in groom works with Houdini 19.0.657 and we load fur as .abc and shaders as .vrscene into 3dsMax 2023.3. Everything is render with Vray6 (6.00.08 build for Max and 6.00.21 for Houdini).
Maps from surfacing are loaded in Houdini with a V-Ray MetalmageFile, color is plugged into a V-Ray BRDFHair4 into the dye_color. The shader is then load as a .vrscene into a VRayVRmatMtl in Max.
But once it's load in Max, it looks like the UVs are scrambled.

left side is from Houdini, right from Max :



I tried various options on the diffuse to see the differences of render in Max, only the option in the tab UV, Type : Projection give something similar (but it's not what I want).

I gave a try re-creating the same shader in Houdini 18.5 and VRay4 and the map appears correctly this time (same groom from Houdini 19.0).

shader from Houdini 18.5 loaded onto the same groom :


I can provide scenes from each versions if needed. Let me know if you need more informations or if you know about this issue.

Thank you for reading me.

[bdancer]

Well, the issue comes from the fact that in Houdini/Maya UV channels are name based, while in 3dsmax all channels are index based.
You need to set "First channel index" to 0 (https://docs.chaos.com/display/VMAX/VRayProxy) at the VRayProxy node loading the Alembic file.

> I can provide scenes from each versions if needed.

If this won't help, yes, the scene files may be helpful to figure out a workaround for you.

[anais_martin]

I've should said it the first time, but it's our temporary solution. But, forcing to the first map reorder this order and we're loosing our pRef information.


A zip file is uploaded with our Houdini and Max scene.

[bdancer]

Ok, I'll check what could be done, tnx!

[bdancer]

Alright, I've made some changes to the V-Ray for 3dsmax and todays nightlies (and stable nightlies) will render vrscene materials with Alembic without a need of any adjustments.
Could you please check if it works for you?

[anais_martin]

Works great on my side!



I've used VRay 6.00.21 and 6.10.09 build if anyone else meet the issue. Thank you for your help.

[bdancer]

> Works great on my side!
> Thank you for your help.

Great! Always welcome

[pingus]

Hello
Thanks for helping.
Do you have any ETA for the next release ? I'd like to wait for a stable version instead of deploying a nightly build

[bdancer]

> Do you have any ETA for the next release ?

The change is included in the "stable" nightly builds (https://nightlies.chaos.com/#/vrayma...ble/stable_6.1 and https://nightlies.chaos.com/#/vrayma...ble/stable_6.0).
Those builds are basically release builds with minor additions/fixes like this one.