Scenario Blender Sculpting

Sculpting (heads and characters, Blender 5.2)

Expert sculpting is structure first and surface last: masses blocked with stated planes and corners, proportions locked at low resolution, every stage judged by eye through a long lens, and appeal as the final test, not the mesh numbers. The agent builds blockout and primary forms headless (scripts/bx_sculpt.py: smooth-blend Clay, plane cuts, numpy brushes) and does client-quality surface work with Blender's real brushes in a live GUI session (bx_gui). If a sibling skill named here is missing from your available skills, ask the user to install it (npx skills add scenario-labs/skills --skill <name>); unattended, proceed from tool schemas and flag the gap.

REQUIRED BACKGROUND: scenario-blender-expert (execution channel, review loop, 5.2 API changes).

Stance (the expert delta)

• Planes are stated, not found. Thelen cuts plane borders with Draw Sharp and re-cuts them whenever a face "looks off"; Naydenov simplifies into planes, then smooths; Reinhardt uses Scrape, Trim and Line Project for clean cuts. Executable form: give the plane (point + normal) to Clay half-space clips or plane_cut / corner_cut. A flatten or scrape dab fits its plane to the ball under it, so it follows the ball.
• The jaw is a block with a gonial corner, the cheekbone a mass with its own lower plane. Zarins: the gonial angle is the age and sex dial, steep in adult males; the widest face point is the top of the zygomatic arch. Naydenov: the cheekbone runs from the ear down and forward, only its lower edge shows. Thelen: bone plus tissue, never razor sharp.
• Fix mass upstream; planes only restate. If re-cutting planes does not fix the look, the problem is mass or proportion (Thelen's diagnostic). Measured: plane cuts on a balloon jaw flipped the form metric but rendered as a gem facet; rebuilding the jaw block fixed it.
• Low resolution as long as possible. Abbitt: smoothing is strong only on big polygons; Thelen: lock proportions coarse. Symmetrize after every remesh (Keelan Jon), then a global relax (Kaspar FDscc66fC90 00:11:55).
• Indicate small landmarks early (nostrils, brows, eyes): Yan found a too-wide nose from the nostrils (vB7kPWjBgQI 00:05:11).
• Stylize by consistent exaggeration (Yan: pick it in minute one, make neighbors follow; a long face needs a smaller skull, not a stretch).
• A concept head needs its cues. Thelen: hair makes a male head read better (00:48:58); Naydenov: hair changes the read a lot (00:53:05). An "adventurer" with no hair or costume reads as a bald mannequin.
• Asymmetry and expression live on a shape key; the basis stays neutral and symmetric (Kaspar f-mx-Jfx9lA 00:09:44; Thelen 00:38:27). Expression tests expose proportion errors; fix them in the neutral (Kaspar 00:10:49).

Establish first

Workflow

0. Design table. G = S.head_guides(H), a STYLE dict (the one or two exaggerations), the cue list, and the landmark points of the planes: gonion, chin bottom, cheekbone. GATE: written down.
1. Blockout (voxel H/40). Default for heads: Clay. Cranium ellipsoid clipped by skull side and front-taper half-spaces; a jaw sd_round_box BEHIND the mouth mound, clipped by side, underside and ramus planes through the gonion; a square chin block; cheekbone ellipsoids along the ear-to-cheek line with a lower plane; mouth mound; brow ridges; nose; neck leaning about 15 degrees; ears; frontal box around the eyes. Blend big masses at 0.08 to 0.15 H, clip edges at 0.02 to 0.03 H. Option: union_remesh of primitives (rounded_box is a Catmull-Clark blob that reads as a ball: never use it for a jaw). GATE: 1 component; lower_face_report(head, H)["ball"] False; silhouette plus 90 mm renders show a jawline and gonial corner in profile and three-quarter; the exaggeration visible.
2. Primary forms (H/100 to H/110). Rebuild the Clay at the finer voxel with landmarks: sockets (sphere 1.1 x eyeball, smaller than the lids), thin shell lids around separate eyeballs (Keelan Jon's lids from the eyeball, amVAlpxHp8k 00:37:05), nose wings tucked in, ear bowls, neck muscles. Hair and costume as separate Clay objects (to_object(name, symmetric=False) for anything asymmetric). GATE: profile beats; eyes not marbles or bags; hair frames the face; stage_report clean.
3. Secondary (H/130 to H/150, remesh_stage). Lines with crease_line (mouth, under-lip, lid rim) on surfaces facing the projection; nostrils from below. Restate planes with corner_cut / plane_cut only where the mass is right and moves stay small. GATE: under 100k faces (Abbitt), no scratches, cracks or rims in 90 mm renders.
4. Surface finish (client quality): live GUI. Real Clay Strips, Scrape, Crease Polish, Smooth 0.2 via bx_gui (fixed and verified: strokes raycast onto the mesh and pass object-space locations; set_view(frame=obj) first, view_distance a few head heights). Headless numpy strokes suit blockout and primary forms, not polish. Multires only on a settled clean base (Henning Cmi0KoFtc-4 00:16:04).
5. Expression. Neutral symmetric basis; sc = S.Sculptor(head, symmetry_x=False), move_feature the corner, cheek, lower lid, opposite brow; S.write_shape_key(head, "Smirk", sc.co). Size the corner move to the delivery framing (Numbers). Voxel remesh drops keys: last step.
6. Final render. S.final_render(objs, path, direction, lens=90, res=1600) (cavity, framed on real vertices) from front, profile, three-quarter, neutral and expression; open every image.

Inside every stage: render, name ONE weakest link, fix it, re-render (Yan). A metric that passes while the render looks wrong means the render wins.

Numbers