ZBrush paint and render (texture and presentation artist)

Expert paint in ZBrush is observation made systematic: color zones placed by what lies under the skin, pushed enough to survive the shader, judged on neutral and flat views, and baked at a resolution the mesh can hold. For an agent without a tablet most of it is buttons: fills at a chosen intensity through generated masks, zone images projected onto the mesh, and renders that are both measured and looked at. 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-zbrush-expert (bridge, stroke engine, review loop, 2026 traps).

Stance (the expert delta)

• Paint last, at the top level. Polypaint is one color per vertex: a lower level paints blurry, adding levels afterwards breaks it, and the map follows the point count (about 4M points per 2K map; 4K is wasted there) (FlippedNormals).
• Judge on neutral and flat. SkinShade4 or MatCap White01, plus Flat Color. A tinted MatCap makes you overcompensate and the export looks wrong elsewhere (FlippedNormals, Pablo).
• Structure before beauty. Start with a pure yellow, red and blue zone map placed by anatomy: bone and fat yellow, thin tissue red, hollows blue, more blue low on a man. Then cover it with skin color at low opacity so the zones shimmer through (Pablo). For an agent this is also the route that can be checked in numbers.
• Masks are "the real trick" (Pablo): generator, Mask Adjust, Inverse, color through the mask. The agent's big soft brush is FillObject at low RGB Intensity through the inverted mask: it scales with RGB Intensity (FlippedNormals), Pavlovich fills through an inverted AO mask, and the tooltip reads "Fill 3D Object Masked".
• Saturation is the stylization dial (Pablo); paint to be diluted (FlippedNormals). Shaders wash polypaint out. Pick the final renderer before deciding how far to push, and keep realistic skin under the middle of the picker.
• Contrast directs the eye. The strongest value or saturation contrast goes to the eyes, and the eyes and mouth get the most time (FlippedNormals).
• Small and fast, then big and slow (Pavlovich). Test small at a high Error Threshold, compare renders side by side, and rebuild the beauty from passes instead of re-rendering.
• Visibility traps (Maxon docs). A displayed texture hides polypaint. In Redshift only Polypaint materials show paint (Use Material Color 0, white Base), SSS Weight 1 hides it, and MatCaps show no texture.

Establish first

Input	Changes	Default when the brief is silent
Purpose: game albedo, film lookdev reference, stills, color print, concept paintover	whether painted shadow is allowed; map size; deliverable	presentation stills, color kept as polypaint
Renderer	materials, passes, turntable route	BPR. Redshift is a separate application and mx1 product list shows it uninstalled on this Mac (2026-09-24); ask before installing it
Style	saturation target, zone simplification	the upstream skill's style: scenario-zbrush-character-creature is realistic, scenario-zbrush-stylized is stylized
Subject: sex, age, build, skin tone	zone layout and hues	ask once; if still silent, assume an adult of average build with light skin and say so
Color deliverable	UVs, map size, Flip V	vertex color; add a texture only when UVs exist
Images	document size, views, turntable	1920 x 1080 (Pavlovich); front, three-quarter, profile and back; turntable 36 frames for review, 180 (Movie default) at 30 fps for delivery [added]

Workflow

Toolkit: scripts/zb_paint.py, ZBrush-side functions through zp.remote("name", ...); full code in references/procedures.md. Save a versioned ZTL after every stage: there is no undo control.

1. Preflight. paint_state() (level, points, UVs, texture display), recommend_map_size(points), texture_off(), save a ZTL. GATE: top level, map_budget(points, side) passes, v001 on disk. Divide now if needed, never after painting.
2. Setup and base. set_paint_mode("rgb") (Zadd and Zsub off), fill(colour, 100): a dull skin base (FlippedNormals, doc) or pure yellow for the zone route (Pablo). GATE: the Flat front shows the fill color; Colorize reads on.
3. Zone map. Parts (eyes, scarf, teeth, clothes): fill_subtools. Polygroups: review with polypaint_from_polygroups(), fill exactly with zone_fill_by_split() (Duplicate, Groups Split, fill each piece, Project All back with Colorize on). Anatomy on one mesh: skin_zone_plan → zone_image → polypaint_from_image (planar UVs, before real UVs); synthesized Color Spray strokes as the fallback. GATE: skin_zone_checks(stage="zones"): forehead yellower than midface, midface redder, a man's lower third bluer, each by at least one JND (2.3 Lab); visually a clown on purpose (Pablo), every zone on its anatomy.
4. Cover and breakup. Skin color at 20 to 40 percent over the zones (doc RGB about 30; Pablo's low-opacity cover); breakup from zone-image noise or Color Spray strokes. GATE: stage="covered": no clown (at most 5 percent of skin pixels above saturation 0.75 [added]), speckle present.
5. Mask passes with mask_pass: cavity darker and redder at 20 to 40 percent; PeaksAndValleys (PVRange 14) or Smoothness with a pale warm fill; ao_plugin mask with a purple-red undertone (ping after). Pablo's Adjust Colors is a dialog [verify live_p06]; a low fill through the same mask replaces it. Mask data cannot be read: prove a mask with mask_coverage(masked, cleared). GATE: each pass shifts the region statistics a little, together they read as skin, back of the head included.
6. Focus and finish. Eyes: an iris image (dark ring, lighter bottom, darker top, lighter toward the pupil) projected onto the eye SubTool, then slight divergence; lips; selective darkening only where light never reaches unless the renderer adds no AO; a 5 to 10 percent wash for realism. GATE: final skin_zone_checks with eye contrast, then the Flat, SkinShade4 and MatCap White01 sheets (paint_review) judged with references/critique.md.
7. Deliver the color. texture_from_polypaint(path, side, flip_v=True) needs UVs (UV Master on a clone, Paste UVs keeps polypaint); or OBJ vertex color; or Substance Bridge Send PolyPaint. GATE: map budget passes, an asymmetric mark lands where expected, file on disk.
8. Render. Save, set_document_size (small for tests; Resize clears the canvas, the function redraws), render_setup (perspective, shadows, AO), bpr_render or paint_views(..., "bpr") for matched views. GATE: render_checks pass and the renders were looked at at 100 percent.
9. Passes and turntable. export_bpr_pass (may open a dialog); clown pass by subtool_solo_views plus id_pass (paint and polygroups untouched); composite (shadow and AO Multiply through the mask); turntable_frames in short chunks, assemble_turntable. GATE: every frame upright with constant framing; the composite beats the beauty toggled against it.
10. Portfolio and report. Gray form views (colorize_all(False), zb_review.review, restore), albedo and beauty views, ID pass, turntable, one sheet. Report what was measured, what was only looked at, what did not run.

Numbers

Value	Relative to	Source
About 4M points per 2K map; 2K = 4M pixels, about 3M usable at 70 percent UV coverage	map side vs vertex count	FlippedNormals 00:30:32; doc
FillObject at N percent RGB Intensity = N percent blend	the current color	FlippedNormals 00:02:51
Zones at RGB about 30, wash about 10; cover Draw Size 150, zones 100 or less	brush strokes	doc Painting a Head
PVRange 14	Mask PeaksAndValleys	Pablo 01:26:37
Map Border high (frames 4 and 16), FlipV on	Multi Map Exporter	FlippedNormals 00:31:22
1920 x 1080 final; 1280 x 720 or 720 x 405 tests; 3200 x 2133 postcard; inches x 300 ppi print	document	Pavlovich; doc
Error Threshold 0.01 final, 1 tests (4 s vs 9 s); Progressive 64, 25 with denoise	Redshift	Pavlovich 040h 00:44:03
Main light 0.1 (never 0) with an HDRI; EXR gamma 2.2; macOS Redshift gamma 1.8	Light, Background	Pavlovich 00:23:12; doc
Crease Level one below SmoothSubdiv (3 and 4)	soft edge highlight	Pavlovich 00:21:26
Movie Turntable 180 frames by default	Movie > Modifiers	Pavlovich FvpG 00:19:56
Realistic mean HSV saturation < 0.5	skin regions, Flat render	Pablo 01:10:30 (middle of the picker)
1 JND = 2.3 Lab; clown share 5 percent; L* span 50; clipping 0.5 percent; noise sigma 2	gates	[added], calibrate on live renders

Quality gates

• Measurable: paint_state (top level, Rgb on, Zadd off, texture off); map_budget; mask_coverage above 0 before a masked fill; skin_zone_checks on a front Flat render with head_regions_front() or regions projected from landmarks; render_checks (framing, value span, clipping, noise); upright_score on turntable frames with a top marker; files on disk with sizes.
• Visual: Flat, SkinShade4 and MatCap White01 sheets in five views for color, and the BPR or Redshift beauty for the final read. Check each at 100 percent for breakup and edges, and as a thumbnail for zones and values. Look for beige or clown, lips, eye focus, the back of the head, bruises, cut shadows and grain. The rubric is references/critique.md.

Common mistakes

Mistake	Looks like	Fix
Painting below the top level, or dividing afterwards	blurry, pixelated paint; artifacts	paint last at the top level; divide first
Judging on a tinted MatCap	colors fine in ZBrush, wrong elsewhere	SkinShade4, MatCap White01, Flat Color
Mrgb left on while painting	the review MatCap no longer shows; material painted in	Rgb only while painting; M or Mrgb fills only for render materials, on a saved ZTL [added]
Gray sheet of a painted model	color shows on MatCap Gray	colorize_all(False), then restore
Texture displayed	new paint invisible	texture_off()
Raw cavity mask	harsh rings	Mask Adjust with Blur; low intensity
Mask By AO on millions of polygons	slow, inaccurate	the Ambient Occlusion plugin
UV Master on the painted original	polypaint erased	Work on Clone, Copy UVs, Paste UVs
4K map on 4M points	wasted map, soft texels	recommend_map_size
Redshift with a preset material or SSS Weight 1	paint gone	Polypaint material, Use Material Color 0, white Base
Smooth Surface on low-poly hard parts	shading bruises	off; creases with Dynamic Subdivision
Orthographic beauty render	flat, technical look	perspective on
Movie > Turntable from a script	cannot stop; asks about an existing movie	scripted frames plus assemble_turntable
Adding degrees for each frame	flips past 90 degrees	absolute triples from turntable_rotations

Handoffs

• Receives: from scenario-zbrush-sculpting, scenario-zbrush-character-creature or scenario-zbrush-stylized, a final versioned ZTL at its top level with stats() and its last review sheet, plus eyes and parts as named SubTools. From scenario-zbrush-hard-surface, parts as SubTools with creases. From scenario-zbrush-pose-print, a posed ZTL (paint with symmetry before posing when possible [added]).
• Delivers to scenario-zbrush-retopology-export: the painted ZTL, the map side from recommend_map_size, and either the exported color map (texture_from_polypaint) or a request for UVs on a clone before the bake. Multi Map Exporter's Texture from Polypaint runs in that skill's map batch.
• Delivers to the user: the beauty renders, gray and albedo sheets, passes and composite, the turntable MP4 or GIF, the portfolio sheet and the ZTL path, with what was verified.
• Sister teams: scenario-blender-texturing-shading and scenario-maya-expert for lookdev with vertex color or maps; scenario-zbrush-automation for batch renders.

ZBrush 2026 notes

• Redshift needs its separate application; AOVs with OIDN since 2025.1, Cinema 4D-matched materials since 2025.2. BPR is unchanged.
• Substance Bridge (2026.2) sends polypaint to Painter as a fill layer; its Force UV Auto-Unwrap strips every SubTool's UVs.
• Movies: MP4 (MOV on macOS), resized above 4095 px. Mask by Smoothness fixed in 2024; ZRemesher Keep Polypaint since 2023; Ambient Occlusion plugin since 2021.6.
• zb_paint.PATHS tags each path; many are [strings] (label exists in this build) or [verify]. Run live_p01_paint_paths.py first: set() on a missing path is silent.
• Nothing in zb_paint has run in ZBrush yet; 36 offline tests pass; live tests tests/code/zbrush-paint-render/live_p01 to p06.

References

• references/procedures.md: full bridge code for every stage. Load before writing any paint or render code.
• references/critique.md: the rubric, the Z1 and Z2 finishing test cases, and the two evaluation prompts. Load at every gate.
• references/expert-notes.md: the depth by expert with timestamps, the disagreements and what transfers without a tablet. Load when a decision is not covered here.
• references/gui-paths.md: palettes, hotkeys and settings for a human or computer-use agent. Load for Spotlight, dialogs and GUI-only steps.
• references/sources.md: every source with credentials, URLs and timestamps.