texture-uv-material-workflow

name	texture-uv-material-workflow
description	Create and validate Blender UVs, atlases, PBR image materials, decals, and bake targets for Blender and OVRTX. Use when textures stretch, colors are wrong, alpha is black, baking fails, or a material must survive USD/MaterialX handoff. The OVRTX runtime/client is installed and not a required source checkout.
license	Apache-2.0
metadata	{"author":"Max Bickley","version":"0.1","team":"omniverse","domain":"physical-ai","tags":["blender","omniverse","ovrtx","materials","workflow"]}

Texture and UV material workflow

Keep geometry, UV layout, image interpretation, and renderer conversion as separate checks. A successful node edit or Blender preview does not prove that the OVRTX MaterialX/OpenPBR result is faithful.

When to Use

Use when textures stretch, colors are wrong, alpha is black, baking fails, or a material must survive USD/MaterialX handoff. The OVRTX runtime/client is installed and not a required source checkout.

Instructions

1. Copy the source .blend and textures into a caller-owned working/output directory. Record image hashes, dimensions, intended color space, and mesh identity. Use stable UV-layer and material names.
2. Choose unwrap, projection, or atlas layout by surface type. For a reference plane or logo, register the front-facing UVs to measured image bounds; for a closed asset, inspect front, back, and side coverage separately.
3. Use sRGB for base color/emissive color images and Non-Color for roughness, metallic, normal, bump, AO, and masks. Connect normal images through a Normal Map/Bump node, not directly to color.
4. For atlases, map each mesh region into its own declared rectangle. Do not apply a whole atlas to every part. For alpha, connect image alpha and enable the documented blend/clip mode; reject black backing planes.
5. For baking, use the supported engine and an active image target with a valid UV map. Preserve cage, margin, resolution, and color-space settings in the report; save the bake as a derived artifact.

Read references/bpy-recipes.md before authoring or repairing UVs and image materials. It contains Blender 5.1 patterns for context-free planar UVs, context-prepared unwraps, reachable Principled materials, normal maps, alpha, polygon material assignment, and bake targets. Run each pattern as its own blender-python-execution transaction and verify its JSON postcondition.

Use blender-community-skill-bootstrap to install upstream blender-uv-texturing and blender-materials when detailed optional recipes are needed. Execute them through blender-python-execution so active-object, mode, color-space, and output-path state are explicit and checked.

Validation loop

• Apply a checker or numbered UV test and inspect a camera render for stretching, flips, seams, overlap, and atlas registration.
• Confirm each polygon has the intended material slot and active UV layer; check evaluated geometry if modifiers change topology.
• Render a neutral Blender control, then use ovrtx-materialx-openpbr with the same camera/lighting to classify each used material as faithful, approximate, unbound, or runtime-unavailable.
• Diagnose in order: runtime/readback → material identity/binding → texture path/UV/color space → light/exposure/display transform → individual lobe. Do not alter albedo to conceal a tone-map or lighting problem.

Run the read-only scripts/audit_material_uv.py through Blender Python after authoring and before render/export. Require status: pass for the visible meshes in scope. A pass requires at least one renderable mesh, valid reachable material outputs and image files, role-appropriate image color spaces, assigned polygon materials, required UV layers, finite UV coordinates, no non-UDIM coordinates outside the unit tile, and no nonzero-area face collapsed to zero UV area. Treat orphan image nodes and unused material slots as cleanup warnings; inspect them even though they do not fail the audit. Declare UDIM use with a reachable tiled image or the object boolean property uv_allow_udim.

For MCP, prepend MATERIAL_UV_AUDIT_REQUEST = {} and append the complete audit script in the same execution call; require the printed JSON to pass. For a saved caller-owned scene, use blender --background scene.blend --python scripts/audit_material_uv.py; a failing audit exits with status 2.

Handoff

Summarize the objects/materials changed, whether the audit passed, and any remaining color-space, UV, or dependency issue. Include hashes, the complete JSON audit, checker/bake previews, or a dependency inventory only when the caller needs a reproducible handoff or review artifact. Keep source references and image planes out of final USD/GLB unless requested.