Hairworks Dynamic control

[pervokpetr]

Original Post: August 02, 2017

1. First of all - normals not packed, they shifted somehow and looks very similar to my packed normals, but they not packed, I was wrong. Problem with shading was due to nvhairworks ignored my environment data and environment reflections was messed up.

I tried implement some of dynamic params for hairworks (only a few from many):

Answers on some questions:
1. hair movement - in opposite to previous hair realisations, in hairworks hair generated across growth mesh surface, according to density parameter. But like in ragdoll hair there is the same propblem - stiffness vs movement. Stiffness value close to 1 allow to keep initial hair shape, but decrease hair ability to move, stiffness value close to 0 allow hair move free, more natural, but completelly ignore initial hair shape. Moreover there is 6-7 different stiffness parameters and I do not clearly understand relation between it.

2. head mods - the hairworks use growth mesh to generate hair, the growth mesh fitted for some head, if you use different head mods, then you probably will had some mismatch between head and growthmesh, this can produce some gap between head and hair (you can see it on previous videos, where my growthmesh was created from head from body.bs, but then I redid growth mesh from head mesh and gap was significally reduced). I'm think that such problem can be solved if we will use growthmesh a bit smaller then head and will create hair guidelines with respect to this. Also additional transform from pass file will be used to adjust hair position.

3. creation - for now I can't fully answer on this question, because I did not solved problem with collisions, but for now I used plugin for 3dmax and nvidia hairworks tool for hair creation, in theory anyone can try create hair for hairworks, but this is not simple task even if it look like simple - for now I see that polygon distribution on growth mesh not good and should be redone, hair guidelines also do not created well - produce some bad looking places on hair. Also I never heard about hairworks plugin for blender.

4. Shading - this will be generic shader for all hair + a lot of dynamic params to adjust hair looking - this is how I see it. Experiments with shading show me that some code in hook can/should be redone. Trying to pass all required data for hair pixel shader I found that probably will be better if I combine some of shader data buffers to reduce amount of "set" operations and amount of used buffer slots.

5. Performance - hard to say, because I'm working in DEBUG mode in this mode I have fps lower in twice, but it looks like there is no significant fps drop. Maybe it just because collisons do not work for now, can't tell for sure.