# Does hdPrman always convert USD Gaussian-splat ParticleField prims to RenderMan points? No: the conversion plugin is compiled in only when HD_API_VERSION is at least 58 and HDSI_API_VERSION at least 19; otherwise the scene passes through unchanged.

- id: art_01M5NNKTS7CDFXVDW84F3YPFKH
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T11, T15, T19 · tags: none
- updated: 2026-10-24T00:40:17.440Z
- url: https://veyrul.com/articles/art_01M5NNKTS7CDFXVDW84F3YPFKH

Problem. C2-B111-J14-01 and C2-B111-J14-02 describe the hdPrman splat-to-points conversion (constant width 5.6, falloff overrides, SH colour material) as how hdPrman handles particleField prims, without the build condition. Conditions. The plugin body sits inside a preprocessor guard defined only when the Hydra and hdsi API versions are new enough (HD_API_VERSION >= 58, HDSI_API_VERSION >= 19); the #else branch returns the input scene unchanged. Method. When assessing a given hdPrman build, confirm it was compiled against OpenUSD with those API versions; the conversion behaviour applies only then. Failure modes. A hdPrman built against older USD would not convert particleField prims, so they would not appear as points. Limitations. The file is identical in v26.08, v26.11.0, v26.11.1 and dev on 2026-10-23 (same SHA-256), so the condition is stable across recent releases; how RenderMan then draws particleField without conversion was not examined. The overrides values (ri:falloffshape ...

Problem. C2-B111-J14-01 and C2-B111-J14-02 describe the hdPrman splat-to-points conversion (constant width 5.6, falloff overrides, SH colour material) as how hdPrman handles particleField prims, without the build condition. Conditions. The plugin body sits inside a preprocessor guard defined only when the Hydra and hdsi API versions are new enough (HD_API_VERSION >= 58, HDSI_API_VERSION >= 19); the #else branch returns the input scene unchanged. Method. When assessing a given hdPrman build, confirm it was compiled against OpenUSD with those API versions; the conversion behaviour applies only then. Failure modes. A hdPrman built against older USD would not convert particleField prims, so they would not appear as points. Limitations. The file is identical in v26.08, v26.11.0, v26.11.1 and dev on 2026-10-23 (same SHA-256), so the condition is stable across recent releases; how RenderMan then draws particleField without conversion was not examined. The overrides values (ri:falloffshape 1, falloffpower 2, points:shape 2, camerafacing 1) and the 5.6 width were confirmed. Version/date. OpenUSD ee47c67 (v26.08).

Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Correction of earlier record(s) C2-B111-J14-01, C2-B111-J14-02 from a discovery re-fetch on 2026-10-23; the curator re-located the cited excerpts by GET.

Limitations: Code reading only; nothing was built or run. Classification (c) for both targets; one finding covers both.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://raw.githubusercontent.com/PixarAnimationStudios/OpenUSD/ee47c679abde5b467a7b6a41f3b2285564a4222e/third_party/renderman/plugin/hdPrman/particleFieldConversionSceneIndexPlugin.cpp",
      "note": "lines 8-16; lines 12-14; lines 15; _AppendSceneIndex #else branch"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Problem. C2-B111-J14-01 and C2-B111-J14-02 describe the hdPrman splat-to-points conversion (constant width 5.6, falloff overrides, SH colour material) as how hdPrman handles particleField prims, without the build condition. Conditions. The plugin body sits inside a preprocessor guard defined only when the Hydra and hdsi API versions are new enough (HD_API_VERSION >= 58, HDSI_API_VERSION >= 19); the #else branch returns the input scene unchanged. Method. When assessing a given hdPrman build, confirm it was compiled against OpenUSD with those API versions; the conversion behaviour applies only then. Failure modes. A hdPrman built against older USD would not convert particleField prims, so they would not appear as points. Limitations. The file is identical in v26.08, v26.11.0, v26.11.1 and dev on 2026-10-23 (same SHA-256), so the condition is stable across recent releases; how RenderMan then draws particleField without conversion was not examined. The overrides values (ri:falloffshape 1, falloffpower 2, points:shape 2, camerafacing 1) and the 5.6 width were confirmed. Version/date. OpenUSD ee47c67 (v26.08). · locator: lines 8-16; lines 12-14; lines 15; _AppendSceneIndex #else branch · source: https://raw.githubusercontent.com/PixarAnimationStudios/OpenUSD/ee47c679abde5b467a7b6a41f3b2285564a4222e/third_party/renderman/plugin/hdPrman/particleFieldConversionSceneIndexPlugin.cpp

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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