Aaron Kimbrell bea6b17b25 feat(ugc): hidden faces removed as LU Toolbox's Remove Hidden Faces decides them ...

The 42 depth renders only saw faces in direct view, so faces reached only by
bounced light (interiors, recesses, rooms seen through openings) were removed.
UgcHsr traces the paths LU Toolbox's Cycles bake traces, directly from points
on each opaque triangle, and removes a triangle only when none of its paths
reaches the sky:

- points in rows along the triangle's longest side, hsr_sample_spacing apart
  (0.1143, 7 x 7 on a stud-sized square), at least hsr_min_points (28, the
  texels LU Toolbox bakes for a triangle), at most 4096
- hsr_samples (8) paths from each point, at most hsr_bounces (8) bounces, as
  Cycles 3.1 samples the bake material (Principled BSDF defaults: Burley
  diffuse and GGX specular, defensive sampling, Filter Glossy, 4 glossy
  bounces, Russian roulette from the second bounce, ensure_valid_reflection);
  no direct sky sampling (Cycles doesn't sample a flat world as a light)
- hsr_ground_plane: LU Toolbox's black box under LDD's floor
- decided per triangle, deterministic per model; triangles without area removed
- the VC pre-pass isn't done

Checked against LU Toolbox's operator in Blender 3.1.2 on the same meshes (27
models, 937,814 triangles): 501,362 removed there, 501,172 here, differences
as large as LU Toolbox's own between seeds. optimize_resolution is retired;
remove_hidden_faces=0 makes the same files as before.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2026-09-28 22:31:24 -05:00

23 KiB

Raw Blame History

View Raw