How would you render a wool roving ball in real-time?
polycounter lvl 6
Something like above.
It seems I would need 3 things:
- unwrap the model specifically to create a directional roving appearance, plus some random white fluffy noise.
- add hair card (aka fins) on model surface then use shader to render small hairy bits at grazing angle.
- use a better shading model than default lit.
Questions:
- I don’t think standard cloth model include this type of materials, can I fake the shading via anisotropy? If so, how?
- I thought about using displacement or bent normal to create small occlusion of layered threads, but really I have no clues if this is the best approach.
- I would like to have a material that can apply to any object without relying on manual unwrap, but I can’t think of a way to create meaningful directional roving on arbitrary surface.
any help appreciated!
It seems I would need 3 things:
- unwrap the model specifically to create a directional roving appearance, plus some random white fluffy noise.
- add hair card (aka fins) on model surface then use shader to render small hairy bits at grazing angle.
- use a better shading model than default lit.
Questions:
- I don’t think standard cloth model include this type of materials, can I fake the shading via anisotropy? If so, how?
- I thought about using displacement or bent normal to create small occlusion of layered threads, but really I have no clues if this is the best approach.
- I would like to have a material that can apply to any object without relying on manual unwrap, but I can’t think of a way to create meaningful directional roving on arbitrary surface.
any help appreciated!
Replies
- I tried the cloth material type today in Unreal, and it does create a significantly closer image to the wool roving (overwriting the roughness specular to something more diffused). One remaining question is whether I should use non-constant "fuzz color" parameter, is it a purely artistic parameter?
- I still have troubles producing small occlusion between strands (perhaps fuzz color can help?), but larger AO are well-served by baking occlusion map from a highpoly model.
- I did go with a fully unwrapped object with uv following specific directions, this allows for better roving textures. Unfortunately the method comes with some uv stretching when unwrapping as a continuous uv island, I am unsure which method can fix it.
- I am not sure what I should do to replicate those tiny white strand that follows the general wool roving directions, I tried base color, normal, roughness, emission, fuzz color, none looks quite right. What's the microscopic physics (BSDF) here and which parameter can best simulate its effect?
it's basically hair, use a hair shader