From FreeCAD Documentation
- This command can be used as the last step in a traditional constructive solid geometry workflow.
- It may help to clean up the model before applying other features, such as fillets.
- Cleaning up an object may prevent 3D printers from printing unwanted edges once the object is exported to a mesh format.
- This command can also be used after converting a mesh to a shape (Part ShapeFromMesh).
- By default this command creates parametric (linked) copies. There is fine-tuning parameter to change this to non-parametric copies. More information about parametric/non-parametric copy behavior can be found in this forum post.
- Some interesting information about what is happening with placement and how to access by Python can be found in this forum post.