well why solidworks produces modesl more solid than something like autocad. It still doesn't produce perfectly manifold models that are 100% suitable for 3d printing.
Almost no conventional cad program does.
A lot are bringing out add on modules that better prepare a model for 3d printing - but I would think that a straight solidworks model will pretty much always need some post processing to make it 100% suitable for 3d printing.

Currently printing a glande test for use in a sling bullet mould. I'll see if I get the same issues with that that i get with spheres.

(couple minutes later) yeah same issues. Good job I'm making a mould for clay :-)
Don't envision any issues with the void in a mould.

Pretty sure it's a heat issue - the further away from the plate - the less problems I get.

sphere issues_800x425.jpg