Baking Hair?I

oXYnary

Is there any possible way to bake a texture of cg created hair on a 3d model shaped the same dimensions as the hair itself (including the alphas)? Meaning you use your hair plug in whatever 3d program your using. Make a simple low poly form that contours to the way the hair flows, and then bake the hairs information unto this forms uvw space.

spacemonkey

creating realistic hair is one of the biggest challenges facing acharacter artists using next gen engines.. I cant offer any help with what your looking for Oxynary.

CrazyButcher

I remember that mankua's texture tool thingie (http://www.mankua.com/kalderabottom.htm) could create alpha maps. However never had the software.

The other problem would be that often hair plugins dont create geometry like the rest, but use their own stuff when being rendered, this could be a problem when trying to use such tools.

thomasp

with the current hires-hair solutions, it's far too time consuming to create complex haircuts. have you ever spent days placing control curves and adjusting masks and face endless preview render times with one of those?
alpha mapped polys are so much faster and direct to work with if you need to have the hair as polys anyway.

but at least with the old shag hair you could convert it into a really complex piece of geometry. never tried with the newer tools.

Eric Chadwick

I think we're still best served by manually placing long curved fins (or squashed tubes), reusing the same painted texture on each.

Specular is a problem I haven't solved yet though, without requiring an anisotropic specular. The specular needs to be squished out in a direction perpendicular to the hair growth direction. So you generally want the specular to wrap around the head horizonatally, splashing sideways across the hair planes.

Some interesting reading here, where they're using hardware-accelerated anitaliased splines for offline-rendered hair. Look at the third paper down, "Algorithms for Hardware Accelerated Hair Rendering."
http://www.game-tech.com/reading.htm

I'm curious how people are handling the alpha-sorting problem. If I'm using alpha-test, there's no sorting problem, but the hair is too clunky. If I'm using alpha-blending, then I need some way of telling the vertex cache which order to render them in. Are people just using a particle-spawn approach, re-sending the hair chunks every nth frame or so?