houdini-gsplat-relighting

Gaussian Splat relighting

Use the typed tools in this package for the cross-context handoff:

1. Inspect the SOP output and confirm point attributes and provenance before changing it. The preflight recognizes Houdini-native GSplats and standard 3DGS PLY exports (f_dc*, rot*, scale*, opacity, and f_rest*). A public reconstruction showcase requires splats trained from at least three views of the same subject with solved camera poses. It also requires a typed camera-pose source and validation state when the capture uses a calibrated or estimated turntable. Estimated turntable poses remain blocked from public showcase use until optimizer or reprojection validation passes. It requires complete subject coverage and held-out evaluation over at least eight views with PSNR >= 25, SSIM >= 0.8, and LPIPS <= 0.2. These are publication gates, not guarantees that anatomy or identity is correct. Anatomy fidelity is a separate mandatory public-showcase gate: all evaluated regions from the fixed 12-region checklist must pass, silhouette IoU must be >= 0.90, normalized landmark error <= 0.03, thin-structure recall >= 0.85, and at least three novel views must be evaluated.
2. Prepare it with Houdini Bake GSplats when normalization is required, then Labs Normals from GSplats and/or Delight GSplats. Keep spherical harmonics enabled when the source provides f_rest* coefficients.
3. In Solaris, use Relight GSplats with USD lights, a render camera, shadows, shadow bias, and optional dome/HDRI lighting. Use houdini-parameters for version-specific Labs parameters that are not exposed by the setup tool.
4. In Copernicus, import the prepared or relit SOP result and use Rasterize GSplats with camera metadata. The setup tool can append Sharpen, HSV, Gamma, and Premult nodes and set the H22 network resolution; use parameter skills for further interactive tuning.

The expected handoff attributes are P, Cd or albedo, N, orient, scale/pscale, opacity, and optional GS_SPH_R/G/B plus ao. The setup tools resolve Labs node type aliases at runtime because Labs asset namespaces vary between Houdini 22 builds.

Procedural meshes sampled into points are synthetic point clouds, not captured Gaussian Splat reconstructions. They may test relighting mechanics, but must not be presented as reconstruction evidence or public GSplat showcase input.

The fixed anatomy checklist covers the head capsule, compound eyes, antennae, mouthparts, thorax, abdomen, forewings, hindwings, forelegs, middle legs, and hind legs, plus tarsi/claws as an independent region across all six legs. anatomy_region_count may include additional documented regions, but anatomy_regions_passed must equal the total evaluated count. The bounded public inputs accept at most 64 regions and 64 novel views; normalized metrics must be finite values in [0, 1].