As I added some improvement tips, I copy here the PT review:
Origin in mid air is wrong. I think it should be placed at bottom surface, in the middle of bottom cavity. Now it's not so obvious since the cavity is slanted...
Otherwise there are many weird split quads/triangles in the middle of the shape. You should run rectifier BEFORE symsplitter (don't forget to update rectifier if it chokes on too large files http://www.philohome.com/isecalc/rectifier.htm)
Also you have many useless condlines in the middle of planar surfaces. Run Edger2 with "delete existing condlines" option to avoid that.
Origin in mid air is wrong. I think it should be placed at bottom surface, in the middle of bottom cavity. Now it's not so obvious since the cavity is slanted...
Otherwise there are many weird split quads/triangles in the middle of the shape. You should run rectifier BEFORE symsplitter (don't forget to update rectifier if it chokes on too large files http://www.philohome.com/isecalc/rectifier.htm)
Also you have many useless condlines in the middle of planar surfaces. Run Edger2 with "delete existing condlines" option to avoid that.