Primvar Data Management#

Utilities to author and inspect UsdGeomPrimvars

UsdGeomPrimvars are often used when authoring UsdGeomPointBased prims (e.g meshes, curves, and point clouds) to describe surface varying properties that can affect how a prim is rendered, or to drive a surface deformation.

However, UsdGeomPrimvar data can be quite intricate to use, especially with respect to indexed vs non-indexed primvars, element size, the complexities of VtArray detach (copy-on-write) semantics, and the ambiguity of “native” attributes vs primvar attributes (e.g. mesh normals).

These classes aim to provide simpler entry points to avoid common mistakes with respect to UsdGeomPrimvar data handling.

Classes#

usdex::core::PrimvarData: A templated read-only class to manage the components of UsdGeomPrimvar data as a single object without risk of detaching (copying) arrays.

Typedefs#

usdex::core::FloatPrimvarData: An alias for PrimvarData that holds VtFloatArray values (e.g widths or scale factors).
usdex::core::Int64PrimvarData: An alias for PrimvarData that holds VtInt64Array values (e.g ids that might be very large).
usdex::core::IntPrimvarData: An alias for PrimvarData that holds VtIntArray values (e.g simple switch values or booleans consumable by shaders).
usdex::core::StringPrimvarData: An alias for PrimvarData that holds VtStringArray values (e.g human readable descriptors).
usdex::core::TokenPrimvarData: An alias for PrimvarData that holds VtTokenArray values (e.g more efficient human readable descriptors).
usdex::core::Vec2fPrimvarData: An alias for PrimvarData that holds VtVec2fArray values (e.g texture coordinates).
usdex::core::Vec3fPrimvarData: An alias for PrimvarData that holds VtVec3fArray values (e.g normals, colors, or other vectors).

Typedefs#

using usdex::core::FloatPrimvarData = PrimvarData<float>#: An alias for PrimvarData that holds VtFloatArray values (e.g widths or scale factors).

using usdex::core::Int64PrimvarData = PrimvarData<int64_t>#: An alias for PrimvarData that holds VtInt64Array values (e.g ids that might be very large).

using usdex::core::IntPrimvarData = PrimvarData<int>#: An alias for PrimvarData that holds VtIntArray values (e.g simple switch values or booleans consumable by shaders).

using usdex::core::StringPrimvarData = PrimvarData<std::string>#: An alias for PrimvarData that holds VtStringArray values (e.g human readable descriptors).

using usdex::core::TokenPrimvarData = PrimvarData<pxr::TfToken>#

An alias for PrimvarData that holds VtTokenArray values (e.g more efficient human readable descriptors).

This is a more efficient format than raw strings if you have many repeated values across different prims.

Note

TfToken lifetime lasts the entire process. Too many tokens in memory may consume resources somewhat unexpectedly.

using usdex::core::Vec2fPrimvarData = PrimvarData<pxr::GfVec2f>#: An alias for PrimvarData that holds VtVec2fArray values (e.g texture coordinates).

using usdex::core::Vec3fPrimvarData = PrimvarData<pxr::GfVec3f>#: An alias for PrimvarData that holds VtVec3fArray values (e.g normals, colors, or other vectors).