An opaque handle to native geometry and topology.

Returned by OCEx constructors, modeling operations, and topology queries. Pass it back to OCEx to measure or transform the shape. The resource remains alive while referenced by an Elixir term; retaining a subshape does not require retaining its parent term.

Do not construct this struct or use its :ref field directly. Persist with OCEx.to_brep/1 or OCEx.write_step/2; the handle is meaningful only in the VM that created it. There is no manual close or free operation.