20 Dec 2007 nymia   » (Master)

The Shading of Hair

Been reading tons of stuff about hair, mainly papers from Kajiya and the much later presentation from Thorsten Scheuermann (ATI Research).

From goofing around with the equations to finally buckling-down to implement the attempt using simple tools like Blender to create the geometry and then export the vertices to a render tool like RenderMonkey, I thought I had all the materials ready. Unfortunately, the geometry I generated did not have the tangent data which was required in the fragment shader. To state it simply, I was royally screwed.

What I basically had was the position, normal and some texcoord data. Plus two textures for skinning and masking. With that on the table, the only option was to re-think the phenomena and re-state the formula according to what was available.

The first try failed, it came out just like an ordinary texture splatted on a polygon.

The second was even worse, the specular made it like plastic.

I’ll try again this weekend.


ref: Martin Koster, J¨org Haber, Hans-Peter Seidel

Syndicated 2007-12-20 09:30:31 from Freedom Culture

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