Associate materialId (an IfcMaterial, IfcMaterialLayerSet,
IfcMaterialLayerSetUsage, or any other IfcMaterialSelect) with objectIds
through IfcRelAssociatesMaterial. existing is every
IfcRelAssociatesMaterial in the model: the material's own relationship is
extended, and an object associated with a different material leaves that
association first.
Associate
materialId(an IfcMaterial, IfcMaterialLayerSet, IfcMaterialLayerSetUsage, or any other IfcMaterialSelect) withobjectIdsthrough IfcRelAssociatesMaterial.existingis every IfcRelAssociatesMaterial in the model: the material's own relationship is extended, and an object associated with a different material leaves that association first.