blender-sculpting

Sculpting

The execution model is in blender-core. The handoff goes to blender-retopology-uv → blender-texture-baking.

Agents: what you can and can't do

• Sculpt Mode operators crash Blender in background mode (-b), including mesh_filter. Never enter Sculpt Mode headless.
• Headless or MCP: use scripts/sculpt_ops.py for object-level ops: remesh=SIZE, symmetrize=+X, multires=N, inflate=D, detail=STR,SCALE, smooth=N, apply. Combine these with Geometry Nodes (blender-geometry-nodes: SDF grid booleans/fillets, noise displacement) and shape modeling for procedural organic forms.
• Live sessions with a UI: brush strokes via bpy.ops.sculpt.brush_stroke(stroke=[...]) need a 3D View region override and are fragile. Prefer procedural ops, then show the user with look. Hand detailed brushwork to the human.

Professional workflow

1. Base mesh / blockout: primitives, metaballs, Skin modifier, or a low-poly base at real scale. Proportions first: compare with references and check against a human 1.75 m.
2. Unify: voxel remesh (remesh=0.02 for a 2 m character, smaller for detail) fuses parts and gives even density. Repeat it while the big forms change.
3. Primary forms at low resolution (Grab, Snake Hook, Clay Strips, Inflate, Smooth). Secondary (muscle groups, folds) at medium resolution. Tertiary (pores, scratches, fabric weave) with Multires levels 4–6, or as normal/displacement maps.
4. Dynamic topology (sculpt.dynamic_topology_toggle): adds detail where you stroke. Good for concept sculpting, bad for final topology and multires (it destroys UVs/multires). Use voxel remesh + multires for production.
5. Multires: subdivide (multires_subdivide, Catmull-Clark) on a clean quad base (after retopo) to sculpt high detail that bakes back to the base level (blender-texture-baking, multires bake or high→low).
6. Handoff: export the high (or keep it in-file), retopo to _low, UV, bake normal/AO/curvature, then texture.

Brushes (5.x: brushes are assets in the Essentials library)

Purpose	sculpt_brush_type
Build volume	CLAY_STRIPS, CLAY, CLAY_THUMB, LAYER, INFLATE, BLOB
Shape / move	GRAB, SNAKE_HOOK, ELASTIC_DEFORM, POSE, BOUNDARY, CLOTH, NUDGE, ROTATE, THUMB
Details / edges	DRAW, DRAW_SHARP, CREASE, PINCH
Flatten / hard surface	PLANE (flatten/fill/scrape), MULTIPLANE_SCRAPE
Clean up	SMOOTH, SIMPLIFY (dyntopo), DISPLACEMENT_ERASER/SMEAR (multires)
Masking / grouping	MASK, DRAW_FACE_SETS; Expand (sculpt.expand), mask from cavity
5.0 renamed brush.sculpt_tool → sculpt_brush_type. 5.1 folded the stroke options into brush.stroke_method (DOTS, DRAG_DOT, SPACE, AIRBRUSH, ANCHORED, LINE, CURVE). 5.2 moved automasking to brush.mesh_automasking_settings / paint.mesh_automasking_settings.

Rules of thumb

• Sculpt at real scale, with scale applied. Brush radius is in screen space but strength and remesh sizes depend on scale.
• Use symmetry (mesh.use_mirror_x, radial: mesh.radial_symmetry) on characters until the asymmetry pass at the end.
• Face Sets organise parts (head, torso, hands). Hide them and mask by face set to isolate.
• Watch density: a 2 m character at voxel 0.005 is already millions of polys. Keep viewport FPS usable and work up in levels.
• Silhouette first. Check from several angles in flat matcap (look shading solid) before adding detail.
• Floaters/kitbash for hard-surface details on organic models: separate objects, combined at bake time.
• Before baking, run blender-asset-qa on the high (no inverted parts, no huge self-intersections in the bake range).

Gotchas

• voxel_remesh destroys UVs, vertex groups (unless preserve attributes) and multires levels. Do it before UVs/rigging.
• Multires + topology changes don't mix: never edit the base topology after subdividing (apply the base or rebuild).
• symmetrize on a non-centered object mirrors across the object's local axis. Center the origin on the symmetry plane first.
• Sculpting on shape keys: enable use_shape_key_edit_mode and sculpt on the active key (facial work, blender-facial-shapekeys).