CGTalk - Shag Hair Texturing Question

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tAstyBITs

06-04-2002, 08:43 PM

I can't seem to get the specular to look right on a patch of shag hair. The texture I got is set to 'hair shader' so I can get the hair specular look. I've tweeked the specular setting so it looks right. But after assinging the materal to the shag-hair-object it dosen't look right the speculars don't appear and when they do they almost seem to be in the places where there not suppost to be. I know it's not right because when I enable geometry it renders out the way is should.

Is it possible the get the geometry hair to look the same as the non-geometry hair?

06-04-2002, 11:35 PM

This is the classic problem with Shag (and many apps Hair plugins)...

It tends to light the hair as though the lightsource is coming from the opposite direction.

The solution(s) for this are...

1. Make sure that you have enough hair to truely cover the objects surface - this sounds a bit stupid, but the denser the hair - the less 'spread' the specular.

2. Make sure that all of your lights are casting shadows - more specifically that they are casting composite shadows... a combination of standard Shadow Map (for the geometry) and Hair Shadow Map (for hair-hair casting). This will not only give you more control, but give the machine less to chew on (as long as you hair shadows are relatively low in size)

3. Enable Bezier and Middle Strand shading - this will instantly provide more detail, and therefore give you more density which in turn will provide less scattered/inaccurate highlights.

4. Don't always use the Hair Shader for your material! I know that sounds silly - but the exaggerated anistropic nature of the Hair Shaders speculars isn't always what you want, plus it makes accurate colouring/diffuse levels a real bitch to pin down (being too dark/light...etc) since it affects them much like the Metal Shader.

Let me know if any of these pointers help solve your situation - and if not, I'll be more than willing to take a look at your scene file for any oddness.

G'luck!

:D

tAstyBITs

06-05-2002, 03:47 AM

Hey thanks for the tips. I still need to play around with diffrent texture setting. I'd though I show my first Shag hair set up. Now keep in mind this is just a rough set up I wanted to get the process down once before I did some serious stuff.

http://www.home.earthlink.net/~loriperkins/HairTest.jpg

I still have alot of work to do before I finnish this one. I'm planning on just doing a bust then I want to set it for animating with morphs and bones and maybe some other cool stuff.

Thanks for you help.

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