procedural-materials-and-shaderslisted

# Procedural Materials and Shaders ## Trigger Use this skill when the user: - Wants to create or edit materials from Python rather than the shader editor - Mentions `bpy.data.materials`, `node_tree`, `ShaderNodeBsdfPrincipled`, `inputs[...].default_value` - Needs to generate many materials parametrically (asset libraries, batch import, color variations) - Asks about EEVEE Next vs Cycles material differences - Asks about "Layered Textures" or "the new shader system" (see version-correctness section) ## Required inputs - **What kind of material**: opaque PBR, transparent, emissive, glass, hair, volumetric - **What controls you want exposed**: base color, metallic, roughness, IOR, normal map, etc. - **Render engine target**: Cycles, EEVEE Next, or both. Most Principled BSDF setups port between the two without changes. ## The minimum viable material Every Python-built material follows the same four steps: 1. Create the material datablock with `bpy.data.materials.new(name=...)`. 2. Enable nodes with `mat.use_nodes = True`. This populates `mat.node_tree` with a default Principled BSDF and Material Output. You can keep them or wipe them. 3. Add nodes to `mat.node_tree.nodes` and configure their `inputs[...].default_value`. 4. Wire `mat.node_tree.links` between sockets. ```python import bpy def make_principled_material(name, base_color=(0.8, 0.8, 0.8, 1.0), metallic=0.0, roughness=0.5): """Create a material with a single Principled BSDF wired to Material Output."""