(1) PartNode
u32 tri_group_index Uses the geometry data specified with the shape_tri_link that is specified in Shape. u32 tri_index From NIFF2.0, the index number described in this data is Tri in TriGroup or EnvelopeTri in Envelope or ClusterTri in ClusterShape. The kind of node (TriGroup or Envelope or ClusterShape) and index number of it's node is determined by shape_tri_link and kind_of_node_for_geometry in Shape node linking this Part node.