Falcor's USD importer implements a subset of the full USD specification. The following provides an overview of some of the USD features not supported by the Falcor USD importer.

• UsdPhysics is unsupported.
• UsdVariantSets do not function properly.
• Animation of camera parameters (aperture size, etc.) is not supported.
• Only per-vertex skinning data is supported. In particular, constant skinning data is not supported.
• A maximum of 4 bones per vertex are supported. Additional bones will be ignored, and a warning issued.

• UsdGeomCapsule, UsdGeomCone, UsdGeomCube, UsdGeomCylinder, UsdGeomHermiteCurves, UsdGeomNurbsCurves, UsdGeomNurbsPatch, and UsdGeomPoints are unsupported
• Instancing of UsdGeomBasisCurves is not supported.
• DisplayColor interpolation modes are ignored.
• Pivot transformations are not supported.

• UsdLuxShapingAPI and UsdLuxShadowAPI are not supported.
• UsdLuxCylinderLight and UsdLuxPortalLight are not supported.
• Instancing of lights is not supported.

• Only the metallic workflow is supported. A warning will be issued when UsdPreviewSurface shaders that use the specular workflow are encountered.
• The clearcoat, clearcloatRoughness, occlusion and displacement inputs of UsdPreviewSurface are not supported.
• The bias, scale, wrapS, and wrapT inputs of UsdUVTexture are not supported.
• Transform2d nodes are not supported.