Get Model3DCollection (Children) for objectName (Model3DGroup or GeometryModel3D) or null if model has no children. GeometryModel3D can have children if for it there was a Model3DGroup created (becasue of a hierarchy). In this case there is a (objectName + Reader3ds.GroupNameSuffix) in NamedObjects dictionary.

Get Model3DCollection (Children) for Model3DGroup or GeometryModel3D or null if model has no children. GeometryModel3D can have children if for it there was a Model3DGroup created (becasue of a hierarchy). In this case there is a (objectName + Reader3ds.GroupNameSuffix) in NamedObjects dictionary.