computeMeshNormals

Fully qualified name: usdex::core::computeMeshNormals

Vec3fPrimvarData usdex::core::computeMeshNormals(

const pxr::VtIntArray &faceVertexCounts,

const pxr::VtIntArray &faceVertexIndices,

const pxr::VtVec3fArray &points,

const pxr::TfToken &interpolation = pxr::UsdGeomTokens->uniform,

const pxr::GfVec3f &fallback = pxr::GfVec3f(0.0f, 0.0f, 1.0f),

)

Computes mesh normals for a given mesh topology.

This function computes normals for mesh geometry using vector-area approach for face normals and area-weighted averaging for vertex normals. The computation supports uniform, vertex, and faceVarying interpolations to match USD’s primvar interpolation types. FaceVarying normals are a simplified approach that assigns the same face normal to all corners of each face.

Normal computation assumes right-handed mesh orientation. The winding order of the data should be reversed in advance if that is not the case.

Degenerate faces (with zero area) and vertices with no contributing faces are assigned the fallback normal.

Note

This function is designed primarily to resolve USD validation issues for meshes that lack normals data. For production-quality rendering with sharp edges or complex shading requirements, consider using specialized mesh processing libraries that provide full edge connectivity analysis and advanced normal computation algorithms.

Parameters:

• faceVertexCounts – The number of vertices in each face of the mesh

• faceVertexIndices – Indices of the positions from the points to use for each face vertex

• points – Vertex positions for the mesh described in local space

• interpolation – The desired interpolation type for the computed normals

• fallback – The fallback normal to use for degenerate faces and vertices with no contributing faces

Returns:

Vec3fPrimvarData containing the computed normals, or an invalid one if computation fails.