RWGltf → Quantity Relation

File in src/RWGltf	Includes file in src/Quantity
RWGltf_GltfLatePrimitiveArray.hxx	Quantity_ColorRGBA.hxx
RWGltf_MaterialCommon.hxx	Quantity_ColorRGBA.hxx
RWGltf_MaterialMetallicRoughness.hxx	Quantity_ColorRGBA.hxx