Vray and Xgen

[l1tay2]

Hi all.

I am having major issues trying to render out xgen with vray. When i render, I only get the xgen fur on a lambert, and no color information.

Ideally, I would like to use the vray hair material 3 and a custom ptex map to drive xgen.

I have read and excercised the following tutorials, and chaos doc...and they have not worked for me.
https://www.youtube.com/watch?v=u7ijzPEtIyY
http://erwanleroy.com/rendering-text...-in-maya-2016/

I have vray 3.4 and Maya 2017


Thanks!

[FSGFX]

to load a custom ptex map you need to overwrite the one maya creates... how to do that is shown here in the tutorial you postet...
https://youtu.be/u7ijzPEtIyY?t=929

[Algehov]

Your second link, to Erwan Leroy's tutorial explain how to set it up correctly pretty well.
What part dont you get working?

A few things to look for:
Make sure you assigned your hair shader to the description in the outliner.
Make sure you have the VrayHairSampler plugged into the hair shader, just as if it was a file texture node.
Have you set up your root_color parameter? It has to be color and not float, in the drop down.
Where you able to press create map, and load a texture into the file node that gets created? Did you press the save icon in the parameter window for it to be converted to ptex?
Is there a ptex file for the root_color in the xgen folder that your discription is linking too?

I think we would need some more info to figure out whats causing issues for you.

[l1tay2]

Thank you both for the responses!

I will go back through the tutorial and check through all of these. Ill hopefully have an update this evening.

[l1tay2]

Update:

I got it working.

1) It appears I was not correctly assigning my hair shader to the description node.

2) There was also strange issue when trying to save ptex to disc. It worked itself out over a few restarts and I was able to successfully render a fur ball with root_tip and root_color.

Question: Is there a way to define how strong the root_tip is, as well as the root_color, other than just the color in the ptex files. When i only assigned the root_color, the effect was somewhat weak, which forced me to assign a root_tip as well.

Thank you for all of your help!

[newimaging]

I am having problems using XGen and Vray in Maya. I have tried many options, but so far nothing has worked.
I ave gone through the tutorial several times at " http://erwanleroy.com/rendering-text...-in-maya-2016/ " and have been successful getting a simple model with one UV set with "Zero - to - One UV" parameterization to render the color map in the fur. I need to, however, try to get a more complex model with tiled UV's (Mari tiling scheme) to have the fur render in VRay from and XGen fur setup.

Does XGen successfully Ptex Mari tiled textures? What is considered too many polygons for XGen Ptex calculation?

I have had many crashes trying to get XGen to give me a map of over 1024, what is considered too fine a resolution for XGen Ptex calculation?

How can be sure the VRay hair sampler is actually sampling the XGen Ptex correctly? Is there a way to get a render dump of the processes in VRay?

Thanks for any help you can provide!

[sharktacos]

Question: Is there a way to define how strong the root_tip is, as well as the root_color, other than just the color in the ptex files. When i only assigned the root_color, the effect was somewhat weak, which forced me to assign a root_tip as well.

Thank you for all of your help!

You don't need to use the root and tip parameters necessarily. Instead you can plug the "distance along strand" output of a VrayHairSampler into the V-coord of a Ramp and then plug that into the desired slot on your material.
http://docs.sharktacos.com/vray/xgen.html#renderC

[sharktacos]

I need to, however, try to get a more complex model with tiled UV's (Mari tiling scheme) to have the fur render in VRay from and XGen fur setup

Ptex does not use UVs at all, UDIM or otherwise. The issue I think is that Maya paints on to UVs to make the maps for xGen, and may have issues with painting on to multi-region UDIM UVs. However, if you instead painted the ptex maps in Mari and applied these to your xGen in Maya this should work fine I'd think, even if the model in Maya has UDIM UVs.