Create and assign PBR materials in Blender via Principled BSDF — metals, glass, plastic, fabric, skin, organics. Covers physically-based material recipes with real-world values, Coat layer (varnish/car paint), Sheen (cloth), Subsurface scattering (skin/wax), Transmission (glass), and procedural patt

MCP backend Use when: Any material assignment, PBR setup, shader work, or look dev request in Blender. Before the first Blender call, read [../text to blender/references/mcp backends.md](../text to blender/references/mcp backends.md). Prefer official MCP for shared capabilities; preserve the selected backend for the whole task. Tool names in recipes are client/legacy examples: map them through that reference and its agent host guide. Blender Materials Apply physically based materials to objects. Use only Principled BSDF — it's the only shader that exports cleanly to glTF and matches what other DCC tools expect. The metallic switch — never an in between The single most important rule: Metallic is a switch, not a slider. Set it to 0.0 (dielectric: plastic, wood, glass, skin) or 1.0 (metal: steel, gold, copper). Values between 0.2 and 0.8 are almost always wrong; they produce energy non conservative renders that look "plasticky." Exception: dark mirror lenses (sunglasses) use ~0.8 to combine strong reflection with slight tint — that's a stylistic choice, not strict PBR. Decision tree Reference look handoff If the goal is to match an original/reference image rather than make a generally attractive render, chain load reference look calibration . It owns measurement of hue/saturation/value, object extent, glow/aura color, and before/after look metrics. This skill should then apply the requested material/lighting/render changes within that calibrated target. Recipes (the 12 to know) Each recipe creates the material and assigns it to a target object. Replace 'GEO target' with your actual object name. set input helper — required for some Blender 5.x BSDF inputs In Blender 5.x's Principled BSDF v2, two inputs are flagged enabled=False in the data API: Weight and Subsurface IOR . These are reachable by iteration or index but not by string key lookup — bsdf.inputs['Subsurface IOR'] raises KeyError even though the input exists and its value is respected at render time. This is a Blender 5.x quirk surfaced during v0.4.0 → v0.5.0 validation. Use this helper whenever a recipe sets an input that might be in the disabled but functional state. It works on every input (enabled or not) and is forward compatible if more inputs become disabled in future Blender versions: For inputs that are reliably enabled (Base Color, Metallic, Roughness, IOR, Transmission Weight, Sheen Weight, etc.), direct string key assignment still works fine — the helper is only required where an input is conditionally disabled. Recipe 9 (Skin) uses it because Subsurface IOR is one of the affected inputs. Recipe 1 — Brushed steel Recipe 2 — Polished gold Recipe 3 — Polished copper Recipe 4 — Mirror chrome Recipe 5 — Clear glass Recipe 6 — Frosted glass Recipe 6b — Coloured glass (wine bottle, tinted vials, decorative glass) Using only Base Color to tint Principled BSDF makes coloured glass look flat or metallic . Real coloured glass has volume absorption : light passing through gets tinted by the distance it travels, so thick parts look darker and thin parts look lighter. This is the depth based richness that makes glass read as glass. Pattern: keep the surface near white with slight roughness, attach a Volume Absorption shader to the Material Output's Volume input. Tuning Density : 0–10 = very subtle tint (clear bottle); 20–40 = clear bottle green or amber; 60–100+ = nearly opaque (cobalt blue medicine bottle). Tuning Color : invert intuition — the volume Color is what gets removed from passing light, so for "wine green" use saturated green; for "amber" use saturated yellow orange. Other coloured glass examples (density values updated v0.9.0 after subject class lighting fix): Name Volume Color Density Surface tint Wine bottle (deep green) (0.05, 0.32, 0.10) 80 near white Pale tinted (clear vial) (0.10, 0.45, 0.18) 15 near white Champagne / pale gold (0.85, 0.65, 0.30) 25 near white Cobalt blue (medicine bottle) (0.10, 0.20, 0.85) 80 near white Amber / brown beer bottle (0.80, 0.40, 0.10) 70 near white Ruby red (0.85, 0.10, 0.15) 100 near white Density tuning rule of thumb under neutral/glass class lighting : Density 5–15 = subtle hint of colour (clear + tinted) Density 30–50 = medium tint visible at thin sections Density 60–100 = proper wine/beer/cobalt bottle look (recommended for hero shots) Density 100+ = nearly opaque (artistic / decorative) If under standard 4:1:2 metal class lighting the volume tint washes out (v0.7.0 issue), don't crank density to compensate — switch to subject class='glass' lighting in blender lighting Recipe 0a, which uses softer rim that preserves the volume colour. Critical : Cycles transmission bounces must be ≥ 16 (default 12) for thick or layered colour glass; otherwise rays terminate and the glass renders black on the inside. Pitfall : don't set Base Color to the tint colour AND attach a Volume — you get double tinting that looks wrong. Surface near white, volume does the colour work. Recipe 7 — Matte plastic (red) Recipe 8 — Lacquered plastic (car paint look) Recipe 9 — Skin (light tone) Uses the set input helper because Subsurface IOR has enabled=False on Blender 5.x and isn't reachable by string key lookup. The other inputs work fine either way; using the helper consistently keeps the recipe safe across versions. Recipe 10 — Velvet / cloth with sheen Recipe 11 — Soft silicone Recipe 11b — Emission (light emitting mesh, e.g. lamp bulb, neon sign, screen glow) Emission is a separate shader from Principled BSDF — replace the BSDF entirely with a ShaderNodeEmission and connect to Material Output's Surface input. The mesh becomes a light source itself (contributes to scene illumination in Cycles). Strength tuning — critical for mesh emitters Mesh emission's effective brightness scales with mesh surface area , not just the Strength value. A small sphere at Strength=50 is barely visible; the same sphere at Strength=1500 lights a desk like a real bulb. Use this table for ballpark values: Mesh size Bulb equivalent Strength 1 2 cm sphere (Edison bulb) 40W warm bulb 800 1500 3 5 cm sphere (LED globe) 60 100W bulb 1500 3000 10×10 cm flat panel (LED panel) Indoor light panel 100 300 100×30 cm strip (neon tube) Neon sign 50 150 Large window plane (sky simulation) Daylight 5 20 Rule of thumb : smaller surface area → higher Strength. Doubling sphere radius reduces required Strength by ~4× (inverse surface area scaling). Use (R, G, B) to set colour temperature: Tungsten (3200K) — (1.0, 0.85, 0.6) LED warm (3000K) — (1.0, 0.8, 0.6) Daylight (5500K) — (1.0, 1.0, 1.0) Cool fluorescent (4500K) — (0.95, 0.95, 1.0) Lamp shade — separate flipped normal interior If the bulb sits inside a shade, the shade's INSIDE surface needs to be bright matte (white) so it reflects bulb light realistically. Single mesh shades only show the OUTSIDE material. Solution: duplicate the shade mesh, flip normals, scale 97% smaller, apply bright white material. This gives proper interior glow when the bulb illuminates the shade. Recipe 12 — Procedural wood (10 nodes) Note : procedural materials don't export to glTF. For web/game export, bake to image textures first. PBR values reference For exact F0 reflectance values for any metal: [physicallybased.info](https://physicallybased.info/) — covers 50+ materials. The recipes above use values from this database. Material naming convention MAT {purpose} {subtype} {finish} . Examples: MAT frame metal brushed MAT lens glass dark mirror MAT pad silicone warm gray MAT wood oak glossy Avoid Material.001 , Material.027 . Always rename. Common pitfalls Symptom Fix "Plasticky" metals Metallic must be exactly 0 or 1 Black metal Base color too dark; metals reflect 30–100%; keep ≥0.5 sRGB Roughness 0 = artifacts Use 0.01–0.05 minimum Glass renders black Increase Cycles transmission bounces (Recipe section 11 rendering) Material not visible in glTF Procedural shader; bake to image first Normal map looks wrong Set image texture to "Non Color" color space sRGB on roughness map Set image texture to "Non Color" KeyError: 'Subsurface IOR' (or any other input) Blender 5.x quirk: input has enabled=False ; use the set input helper at the top of this file instead of bsdf.inputs['Name'] When to load references/overview.md Load when: The recipe you need isn't in the 12 above You need anisotropy (brushed metal direction), volume absorption (tinted thick glass), or advanced shader node combos The user asks for material variation across one mesh (Mix Shader patterns) You're baking procedural to image textures for export The reference covers: full Principled BSDF parameter map, 50+ materials database link, procedural texture combinations (Voronoi, Wave, Noise), Sheen + Subsurface deep dives, and bake for export workflow.

blender-materials