fabric_surface

Two-sided fabric surface shader. Lights with the engine PBR from the true-facing normal (back faces flip it, so a cull-none cloth sheet shades correctly from both sides), multiplies the mesh's per-vertex pattern colour into the albedo, overlays a procedural thread weave that modulates albedo and roughness, and adds a grazing-angle sheen term for silk / velvet looks. Pair with a material that sets render: { cull: none } — the fabric_* materials in this world are its configured instances.