Thanks for the angle info, Fredericmenage. The problem with the bosses was that I wasn't creating them from the plane above and protruding them down to the base plane. I also ran into an unusual bug, where every time I went back to the boss properties the slope of the runners would change...
alright, I've got it all laid out now, and it's working. My only other need is to change the orientation. I have a 3-ribbed boss, but I need half of them to be turned 180. Is there any way to do this, or should I somehow create the other set as a second feature?
I'm definitely working with a manifold body, and understand that you can't have edge or point intersections. I've got a cup shape with an absolutely flat bottom, and I'm trying to create bosses at the bottom. I've changed my design based on fredrickmenage's suggestion, so that I'm starting on...
I'm trying to make a boss feature on a planar face, and I get "Boolean Operation on Solid Failed". There are no features that it would interfere with, and it's on an absolutely flat face. Any idea why I'm getting this?