Microstation already has Clipping and Void Clipping Technology, could it be further extended to Facet delete? If user already has the outer boundary (Perhaps in 3D LineString), this tool would reduce the time to delete facet one by one.

Reference of existing way to create mesh:

https://communities.bentley.com/products/microstation/f/microstation-forum/252486/how-to-drop-solid-to-surface