(Resolved) [HOU-3938] HairSampler - position across strand - missing in vray for houdini?

[fred_hopp]

Hello

I can't find "position across strand" on the HairSampler node.

What would be the workflow to have both u+v coordinates on hair in order to texture them like tubes?

Cheers.

[viktor_angelov]

Hello fred_hopp

I am glad to let you know that the bug has been resolved and you can find the fix in the latest Nightly build (4th of August 2023): https://nightlies.chaos.com/main#/vray6houdini/nightly

Any feedback from you is appreciated.

[viktor_angelov]

Hello fred_hopp

Thank you very much for your time and efforts to provide the necessary information to replicate the issue on our side. It is classified as a bug ( HOU-3938 )and escalated to the Development team for further inspection and resolution. We’ll get back to you as soon as we have any updates.

[fred_hopp]

Thanks a lot for having a look at it, Viktor.

[viktor_angelov]

Hello fred_hopp

I am glad to let you know that the bug has been resolved and you can find the fix in the latest Nightly build (4th of August 2023): https://nightlies.chaos.com/main#/vray6houdini/nightly

Any feedback from you is appreciated.

[fred_hopp]

Thank you for this. I'll see if I can use the nightly in production at the place I'm working now. I'll get back to you once I get a chance to try it out.

Thank you very much for the update.

[viktor_angelov]

Thank you fred_hopp Looking forward to your feedback!

[daeschri]

An alternative and imo preferred method is to just use the curveu attribute for this. Thats a more common houdini workflow that is renderer agnostic and what we leverage all the time not just for hair shading but hair cfx deformations.
This way you have a uv attribute for texture use and then a curveu attribute for position along the curve and this is something you can easily manipulate with vex and sops and still use in shading.

David Eschrich
Global Head of 3d
Zoic Studios

[fred_hopp]

Totally agree David.

It's more the "curve V" attribute : "across" I'm interested in (the one for the circumference of the hair tube).
I still have not had time to try the fix out, yet. Will report back once I have.

Cheers.

[fred_hopp]

Viktor.

I finally took the time to try out a recent nightly (from 09/30/23: vray_adv_61009_houdini19.5.403_c517ce1_22524)

I can confirm that it indeed does work now. Thank you.

However, I was almost expecting displacement to work as well, but unless I did not set this up correctly, I could not get it to work.
Attached are a screenshot showing a texture nicely fitting a curve primitive rendered as hair, and another showing failure with displacement.

I attached the failing displacement setup in case you'd like to look into it (if this is at all technically feasible).

Cheers.

[bdancer]

Displacement works only with meshes.