In this post I will detail how to clean CAD geometry in writing. Attend the event for the live demonstration.
1.) in the right hand panel click on the eye icon for all the geometries except the one you want to edit
2.) click on the geometry you want to edit and go into edit mode
3.) go to select > select by trait > non-manifold edges. When you do this all the non-manifold edges will be highlighted. Use this to locate them.
3.5) you can also use x-ray to see through the geometry
4.) upon sighting the non-manifold select all the nodes/edges encasing the hole by holding ctrl + clicking
5.) press F to create a patch
Repeat steps 1-5 to have satisfactory watertight geometry