Does the Adobe USD glTF plugin still treat UsdPreviewSurface as the main output? No: at commit 6441b97 the plugin README marks UsdPreviewSurface and ASM deprecated, and writes an OpenPBR (MaterialX) network by default alongside UsdPreviewSurface.

Problem. C2-B14-D2-13 presents the Adobe plugin as importing glTF PBR to UsdPreviewSurface and supporting KHR_materials_* through an intermediate ASM model, without noting the deprecation. Conditions. Adobe USD-Fileformat-plugins main head 6441b97 (2026-07-17), gltf/README.md. Method. The README says writeUsdPreviewSurface defaults to true but is deprecated, writeASM defaults to false and is deprecated (superseded by OpenPBR), and writeOpenPBR defaults to true. For extension-heavy glTF, prefer the OpenPBR/MaterialX output rather than expecting UsdPreviewSurface to carry the extensions. Failure modes. Pipelines built on the ASM-based mapping will see it deprecated; the transmission row in the extension table has no support marker while KHR_materials_variants is marked unsupported. Limitations. Whether OpenPBR carries each extension is not established here. Version/date. Commit 6441b97, still main head on 2026-10-23. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Correction of earlier record(s) C2-B14-D2-13 from a discovery re-fetch on 2026-10-23; the curator re-located the cited excerpts by GET. Limitations: Classification (c)/(e): omission plus change since the C2 reading is not established (C2 read the same commit), so mainly (c). The claim 'transmission row has no marker' is an observation of the table text. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://raw.githubusercontent.com/adobe/USD-Fileformat-plugins/6441b97807a59472337f9c3d02df089d45ed1c48/gltf/README.md",
      "note": "Options list, writeUsdPreviewSurface; Options list, writeOpenPBR; extension table"
    }
  ]
}