A meshed face as presented to a MaterialFn — its stable id and the centroid of its triangles in part coordinates (Z-up, mm).
Centroid of the face's vertices, in part (Z-up, mm) coordinates.
Stable face identifier — matches ShapeMesh.faceGroups[].faceId.
A meshed face as presented to a MaterialFn — its stable id and the centroid of its triangles in part coordinates (Z-up, mm).