Hair grooming

The execution model is in blender-core. Hair physics details are in blender-simulation, and look-dev in blender-lighting-lookdev.

One call each

scripts/groom.py -- --surface Head --mask Scalp --length 0.15 --children 150000 --clump 0.5
scripts/groom.py -- --surface Head --mask Beard --length 0.02 --droop 0.2 --curl 0.004 --melanin 0.9 --name Beard
scripts/groom.py -- --surface Body --length 0.025 --droop 0.3 --clump 0.3 --name Fur
scripts/groom.py -- --cards Hair --card-count 150 --atlas-res 2048 --out //textures      # game hair cards

How pros groom

1. Surface first: the scalp is a mesh (or the head itself) with UVs (hair attaches by UV) and a vertex group painted where hair grows. That group becomes the density mask, so soft edges give a natural hairline.
2. Guides → children: a few hundred to a few thousand guides carry the shape, and thousands of interpolated children give the volume. Style the guides, never the children.
3. Shape in layers: length, then clump (strands gather into locks), then curl/wave, then frizz/noise, then profile (thin tips). Keep each a separate modifier you can toggle.
4. Comb by hand for anything hero: Curves Sculpt mode brushes (Comb, Add, Puff, Pinch, Grow/Shrink, Smooth, Slide, Density, Delete, Pull Tips). Procedural droop gives a believable base, not a hairstyle.
5. Look-dev under the final lights. Hair reads mostly from specular and depth (clumps catch highlights), not albedo.