[HOU-3941, HOU-3939] Vray Fur distribuition

[david.anastacio]

Hi,

The distribuition in the Vray Fur node seems to be broken, the "Per Area" source option has no effect.

Setup:

Render in "Per Area" mode:


In a side note, what is the recomended workflow with Vray Fur? It only works on poligons (aka, unpacked geo) which leads to very large vrayscenes later. Is there any way to get the fur to work on packed geometry, or to somehow cache the fur?

Also, there is a small typo in the Vray Fur node, the Variance tab currently reads "Varience".

Best,
David.

[Dubbie99]

I've noticed that the per-area checkbox has been broken for a very long time even in 3DSMax.

[david.anastacio]

Hi again,

Gosho.Genchev, any idea on this one, would love to get this one working soon please

Best,
David.

[bdancer]

> Is there any way to get the fur to work on packed geometry

No.

> or to somehow cache the fur?

V-Ray Fur is generated render-time and not written into the vrscene file so there is nothing to cache.

[david.anastacio]

> Is there any way to get the fur to work on packed geometry

No.

> or to somehow cache the fur?

V-Ray Fur is generated render-time and not written into the vrscene file so there is nothing to cache.

Thanks bdancer.

Any idea on the "per area" source issue?

Best,
David.

[viktor_angelov]

Hello david.anastacio

I would like to inform you that the V-Ray Fur Distribution Slider has now been upgraded.

Please, test it in our latest Nightly build and feel free to share any feedback you may have: https://nightlies.chaos.com/main#/vray6houdini/nightly

[david.anastacio]

Thanks for the update viktor_angelov

I need to add another issue that I noticed regarding the fur distribution.
When you apply some fur onto a deforming plane, the distribution changes at a certain frame (1050), it seems that when the polygons contract a bit the distribution gets updated.

See the following rendered example, it's just a plane/box getting bent over time and I'm using "Per Area" distribution:


This is also visible in the viewport preview of the fur:


It could be that we need an option to use a "rest" mesh or a target frame for the initial distribution (as polygons deform and their area changes, the distribution might change over time). And I don't want to use "Per Face" distribution as that will lead to an uneven distribution in some models.

best,
David.

[viktor_angelov]

Hello david.anastacio

Thank you for the information and reference videos!

Could you send us your scene so we can investigate further. You can do that here or by Submitting a Request to our System.

Also, please let us know of your exact V-Ray build and Host application version.

[david.anastacio]

Hey viktor_angelov ,

I attached 2 example scenes of the issue, the small patch of fur from earlier, and a new one using the animated Crag.

On the Crag example, you can see that using a "Per Area" distribution makes every frame I go to have a different distribution, but when I change to "Per Face", the distribution stays the same between frames.



VFH build:
V-Ray for Houdini number:22407 hash:c229ef2 from 26 May 2023 01:01
V-Ray Core 6.00.21 [9ebef0ba] from 18 May 2023

Best,
David.

[david.anastacio]

I think I know what the issue is.

From the 3dsMax V-Ray Fur documentation:

This is what I was suggesting we needed before, and apparently you already have it, you just need to expose it in the Houdini UI.

Best,
David.

[viktor_angelov]

Hello david.anastacio

Thank you for your time and effort to reproduce the situation and share it with us. It has been logged in our system and it's worked on. I will contact you when the improvement is implemented.

[david.anastacio]

Hi again viktor_angelov, I saw some updates regarding HOU-3939 on today's nightly changelog and gave it a try, the new lock to surface and reference frame options are in the UI, but they are not working at all.

In the viewport, the fur distribution is still changing every frame, and if you render the fur you can see that it's static on the first frame (1001).

In the viewport:


Rendered, frames 1001 and 1020:


Best,
David.

[viktor_angelov]

Hello david_anastcio

We appreciate you sharing this with us! I have reached out to the Devs to take a look.

[viktor_angelov]

david_anastcio

Please, send us your scene so we can investigate further. You can do that by Submitting a Request or sending it here.
Please, make sure to include all the HDRIs, assets and textures that might be needed.

Also, please, share a screenshot of your V-Ray > About V-Ray window.

[david.anastacio]

david_anastcio

Please, send us your scene so we can investigate further. You can do that by Submitting a Request or sending it here.
Please, make sure to include all the HDRIs, assets and textures that might be needed.

Also, please, share a screenshot of your V-Ray > About V-Ray window.

Hey

It's the exact same scene I attached in post nº9 above.