I'm a newbie learning to use Blender to produce 3D printable objects, since it is the most flexible software tool on the planet for 3D printing. However, in doing so I realise that I am using only a few percent of its capabilities (e.g. spending all my time in Edit Mode on objects that will never move) and, in particular, creating manifold objects is proving difficult. My object looks like it should look but it is non-manifold in various ways (non-manifold edges, non-intersecting faces, etc.). The original Blender file is here:
I realise that I can improve my construction technique to be sympathetic with the ways of Blender and I can use the 3D Printing add-on to slowly and carefully correct each minute mistake but that seems wrong to me: if the object looks correct then software should be able to generate a 3D mesh that is, near as dammit, printable. Maybe not quite what I drew but corrected to be a printable thing. A modifier of some form: the be-slightly-fatter-more-rounded-and-more-connected-but-don't-bother-me-anymore modifier :-)? FYI the "Make Manifold" option in the 3D Printing add-on doesn't produce a sensible result in my case.
Is such a thing possible and I've just missed it in the many very useful tutorials, or do I need to go through very carefully finding the slivers of errors in my (beginner's) work, which is not much more than a cup-shaped thingy with drill holes? See a acreen shot of the object below, along with one of the manifold-corrected version according to the 3D Printing add-on, the 3D Printing add-on's list of errors and the view of my 'orrible object as seen by slic3r-3d (Prusa edition).
P.S. apologies in advance if I'm the Nth person who's asked this.