Vector flow map to Anisotropy map

[tomtnt]

Hallo
Just wondering how to solve this:
I have a human scanned head model with a texture. I painted a vector flow map in Krita as a base for scattering hairs on head. But, I wonder If I have a vector flow map of hairs directions, would be here an option to convert this vector flow map in to anisotropy map un use it for hair reflection on original model? Vray works with B/W anisotropy map definitions. Krita and some other software knows to paint vector flow map well, but paint anisotropy map is almost imposible due the technology of definition (tough problem between 359 and 1 degree angle)
So, I would need to teach Vray works with anisotropy map in vector flow map definition or somehow convert this map in to B/W format.
I have already get a help how teach forest pack works with vector flow map format. Forest pack works originally with same B/W definition for rotation of oject. What is cool is ability to put a simple script in to forestpack to work with vector flow map. Just see this:
https://forum.itoosoft.com/index.php?topic=4412.0



How to tech vray to use a vector flow map for anisotropy reflection?
Thank you for any help

[vlado]

See here:
https://forums.chaosgroup.com/showth...287#post682287

You might need to tweak the GLSL shader a bit, as the one in Modo uses red/blue whereas it looks like yours is red/green.

Best regards,
Vlado

[tomtnt]

Thank you for a help and another information about aniso.
I have made today some tests as you can see below. What surprised me is a different between the real geometry and shader definition of anisotropy. I have made 900 tubes in my scene on the left side that are bend in to 360 degree circles. Bottom left is also a circle from 900 tubes, but they are rotated in the center to 180 degree. So all tubes goes from center of circle. So, it looks similar for first look, but the reflection result is different for sure and seems to me right.
Hm, on the right side of scene are two planes with GLSL shader with anisotropic map. On top corner is original map from Modo that should represent circle direction.
I need to create a perpendicular directions to the original circle directions. I do not know If my modified texture in the bottom right corner is really perpendicular to circle directions. If would be, the reflection should be same as the real geometry, but it is really different
Unforcunatelly, also the circular reflection of GLSL shader does not match the real geometry reflection
I would like to paint fur directions in the vector flow map definition and use it for better reflections on my horse model.
Tomas

[vlado]

Can you post that scene?

Best regards,
Vlado

[tomtnt]

Hi Vlado,
yes, here is a link to download the scene:
https://www.sugarsync.com/pf/D7185189_06382907_65440270
I have did a little mistake in the material of real geometry that had also anisotropy. Now, this material has no anisotropy and create anisotropy effect only by micro-structure of geometry and renders looks like this:

It is still very different to anisotropy shader.
I am confused what is right - if real geometry or anisotropic shader.
Thanks for a help. Tomas.