Texturing and shading (Blender 5.2)

Expert shading is layered masks feeding physically plausible values: a clean base (scanned set or flat colors), then contrasty black/white masks that place color, roughness, height and subsurface, all editable in nodes. Values are judged under honest light in both engines, and baking comes last, for portability. 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). Baking maps: scenario-blender-uv-baking. Lighting and final renders: scenario-blender-lighting-rendering.

Toolkit: scripts/bx_materials.py (builders, headless painting, checks; exercised by tests/code/blender-texturing-shading/). sys.path.append("<this skill>/scripts"); import bx_materials as M.

Stance (the expert delta)

• Data maps are Non-Color, "not what looks better, what's correct" (Price). Only base color and emission are sRGB.
• Normal map OR displacement, never both (Price, confirmed by Cycles lead Brecht): they encode the same relief. Displacement when heights will be combined or truly displaced; normal map for export and 8-bit safety.
• Masks, not painted color. Kaspar and Price build every effect as a grayscale mask into a Mix or HSV Factor; color lives in the A/B inputs. Masks need contrast (Color Ramp stops pulled in) or they barely show. The same masks drive roughness, height and SSS.
• Realism: scanned set plus masks; stylized: procedural (Price vs Kaspar and Ryan King). Kaspar strips photos to their pattern (blur plus grain extract) and adds grunge himself, and bakes at the end for portability (export, EEVEE load time), not for Cycles speed.
• Micro detail in roughness, not bump, for skin and hair (Kaspar); edit roughness through HSV Value, never by unplugging the map (Price). Specular stays 0.5. Bump Distance is the real height of the map's 0..1: lower Distance, not Strength (Kaspar).
• Judge honestly: Standard view, neutral mid-gray background, Base Color black to read roughness, a hard backlight and a light from below (Kaspar); grazing light for relief (Price); unlit for hand-painted albedo (Abbitt). EEVEE for iteration, Cycles as the truth, and they must match (Kaspar).
• SSS follows anatomy (Kaspar): high on ears, nose, lids, lips, fingertips; low over bone. Black/white mask, Map Range sets values.
• Bevel, AO, Pointiness and Random Per Island are Cycles-only, and Bevel/AO are stochastic [added, measured]: EEVEE shows no Bevel edges; thresholded live masks give 17 to 18% fractional metallic at any sample count. Bake before thresholding, or use vertex curvature.