Maya Hair + Hair Mtl 3 + an object in front with vray Mtl with refraction = no hair

V-Ray V-Ray for Maya Issues
1

I am having an issue where I have an object (let’s say a glass sphere) that passes in front of a character with Maya nHair using Vray Hair mtl3 with cached GI.
I am using Maya 2013 and the latest build of Vray. Any thoughts.

I have tried upping the refraction depth on the glass sphere but have not gotten any different results. I just get a bald head with all the other shader and texture detail minus the hair.

I also did the “glass material --> refraction --> affect channel (all)” and did not get anything either…which seems odd…I will retest this again but needless to say I am hitting some walls.

I am going to test by applying a base vray mtl to the hair and see if I get any differing results. As well, I will try and see if using alternatives to cached GI have any impact.

Other less trial and error thoughts would be fantastic…:slight_smile:

Thanks in advance.

R

2

Can you get me a simple scene? Works fine here…

Best regards,
Vlado

3

We are having the same issue. It is easy to replicate:
1) make a sphere, create hair
2) place a geo plane in front of it, assign vrayMtl, make it refractive
3) hair is not visible through the refractive plane

Any help would be appreciated!

4

I was thinking this might be an issue with PFX, but when I tried the same experiment with PFX (astro turf set to “thin line”) it renders fine through the glass. So does vrayFur. The only thing that does not seem to work is Maya hair.:frowning:

5

Here’s an example scene and render

hairRefr.jpg
hairRefr.jpg660×652 40.1 KB

HairRefractionTest.ma.zip (21.8 KB)

6

I can confirm that it does not work for both reflection and refraction. When hair is created the default value for reflection/refraction is off. But it seems to have no effect. Running build:

[2013/Jul/4|13:51:13] V-Ray: V-Ray for Maya version 2.25.01, revision 22851 from Apr 5 2013, 02:24:28

7

In maya 2012 it works to turn on refraction in the PFXShape render stats. In 2013 the render stats are no longer there.

8

SOLVED: the render stats are gone in Maya 2013 but can be accessed in the render tab of the attribute spread sheet.

Alternately one could use these mel commands (substituting the asset name of course):

setAttr "pfxHairShape1.visibleInRefractions" 1;
setAttr "pfxHairShape1.visibleInReflections" 1;
9

Thank you very much for the feedback.
It seams that Render Stats check-boxes of the hair are not taken into account by Vray.
I am going to report that into our system - and I’ll update you when we have it fixed.

It is very strange why Maya doesn’t reflect Render Stats properties in Attribute Spread Sheet editor for Hair Object - it works for every other type of objects but not for the hair.

Thank you very much again.

10

To clarify: the render stats are in the PFXhair rather than the the HairSystem. These render stats are taken in to account by Vray, but they are turned off by default and hard to find since they do not appear in the attribute editor as of Maya 2013 which would cause many users to conclude they do not exist since most people wont go rummaging through the attribute spread sheet looking for them.

Vray can perhaps do some workaround like having these to get turned on by default when hair is rendered, or have a checkbox in the hairMtl3, but really Autodesk just needs to put the render stats back in the attribute editor. Why they removed it makes no sense.

11

Thank you very much for the clarification - I’m going to add this information into our system, it would be helpful for our Developers.