AnisotropicFun – part1

the following are the pics I created after a few days test session around anisotropy and specifically anisotropic reflections.
these two links from Neil Blevins helped a lot clarifying the subject :
Anisotropic Reflections tutorial
Anisotropic Highlights tutorial

I was looking for a way to synchronize the derivative vectors orientation/patterns and the texture maps used for bump or diffuse to help in the final shading of these kind of materials.
I came up with this idea to use the derivative vectors to drive a 2D directional blur.

Shading is done in XSI/MentalRay using MR physics lib (dgs or mib_glossy_reflection).
All these tests have been done with version 5 of XSI.
Directional Blur is done with ReVisionFX’s RSMBVector inside XSI FXtree.

NoAnisotropy

dgs_only.jpg

derivative vectors are defined using the deriver shader. here north pole at (0,0,0)

deriver_anisotropic.jpg

clean UVs

uv_layout.jpg

rendermapping U derivative vector : this is done using a special VectorState shader and applied as the color of the object . this is rendermapped as a .ct texture to keep negative informations intact.

derivative_u.jpg

transforming the derivative in the UVbasis : the rendermapped derivative is injected in the bump map slot of the material.

derivative_as_bump.jpg

than everything is rendermapped again using rendermap option to render normals in the UVbasis.

rendermap_uvbasis.jpg

if you get rid of the blue component it looks like a typical RSMB vectormap input.

motionvector_like_map.jpg

visualising the vectors with lmVectorViewer

motionvectors.jpg

creating a noise pattern

noise.jpg

applying directional blur with RSMB

rsmbing_the_noise.jpg

using the map in bump and diffuse shaders

cylindre.jpg

part2

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