Files
AnyImage/openspec/changes/archive/2026-09-17-scale-tangent-normals-with-depth/proposal.md
nan 076a8c90f1 Add specifications for two-times upscale and unified depth plane features
- Introduced the two-times upscale specification detailing requirements for unified output, fixed model presets, arbitrary dimensions, and consistent job behavior.
- Added scenarios for existing models, repeated upscale, and handling of alpha preservation.
- Created the unified depth plane specification outlining geometry modes, stable interface, and asset evaluation.
- Defined scenarios for mode switching, relief and camera preservation, and validation of delivered assets.
2026-09-17 17:19:05 +08:00

1.2 KiB

Why

Tangent-space normal maps describe the full-depth surface. When a geometry node reduces its Depth Scale, its shape becomes flatter but the material normal remains at full strength, making surface detail appear too strong.

What Changes

  • Reuse the existing o_normal_reduction geometry attribute as the material-to-geometry contract for tangent-space normal strength.
  • Make tangent-normal depth geometry write 1 - Depth Scale to that attribute, so the material normal strength follows the displayed geometric depth.
  • Extend the existing O Image Layer behavior without changing its attribute lookup or fallback semantics.
  • Make Object Space normal strength follow the same geometry reduction contract.
  • Reuse the existing o_normal_reduction contract for additional Tangent-normal depth geometry.

Capabilities

New Capabilities

  • depth-scaled-tangent-normals: Keep tangent-space material normal strength consistent with geometry depth scaling.

Modified Capabilities

None.

Impact

  • Tangent-normal geometry-group builders, especially Relief Plane.
  • Normal-scale node tests; saved node assets must be rebuilt with uv run node-group build.
  • No server inference format, user-facing modifier socket, or dependency changes.