The resulting model body has no topology.
Structure semantics calling the Geometry and Topology Boolean APIs should handle the well-defined HRESULT error code MODELTOPOLOGY_E_NULLBODY.
In the context of Boolean APIs, a result with no topology (such as a null model body) is returned if the tool body is greater than the blank body (also known as material).
None if the calling code is handling MODELTOPOLOGY_E_NULLBODY properly.
What You Should Do
Report to the concerned application that a null model body has been produced, and that the calling code needs to handle it properly.