Vertex count of this primitive — for byte/triangle accounting by callers (e.g. the 3D-tile cache budget) without retaining CPU geometry.
RTC offset removed from this primitive's positions (see
StaticPrimitiveGeometry.center); [0,0,0] unless loaded with recenter.
OptionalfeaturePer-vertex feature id (for picking), aligned to the mesh's vertices — null unless
loaded with featureIds. buildDrawables pairs it with the baked world
positions to build a CPU pick soup.
OptionalvariantKHR_materials_variants: variant index → material for this primitive, or undefined when it defines no mapping. See GltfStaticModel.setVariant.
One renderable primitive parsed from a glTF mesh as a static (non-skinned) mesh.