Overlap tool


One of the recurring problems when editing BRL-CAD geometry is detection and elimination of overlaps - that is, geometric errors where two solid objects claim to occupy the same 3 dimensional volume. Often, one of the jobs of a modeler working on a large model is to identify and fix what can be a multitude of small overlaps.

The task for the summer would be to develop a Tcl/Tk based graphical tool that helps to view and address overlap problems in a model. Roughly, the steps are:

  1. Run the overlap checker
  2. Review the results and make appropriate changes
  3. Re-run the checker to confirm the changes

When resolving the overlap, it is very useful to see what is overlapping - a wireframe visualization of the individual overlapping components would be a virtual must for any tool proposal. The tool should assist with identifying optimal subtractions (subtracting one big geometry tree from another to clear overlaps is usually a bad idea). It should also allow the modeler to editing the geometry and quickly re-test that particular overlapping combination.


  • src/tclscripts/mged
  • src/tclscripts/archer
  • mged
    • there is an existing overlap tool here (on the Tools menu)
    • it sucks, but look at it.
  • archer
    • has nothing, ideal place to put the new interface


  • Familiarity with C
  • Familiarity with Tcl/Tk