I have a few questions as a new user. I’ve watched many hours of instructional video footage and want to clear up a few issues.
Yesterday I had an odd issue with a zsphere appearing corrupted. I deleted the offended sphere and readded it and that fixed it. See the image. Any idea why that happened?
Doing a radial insert mesh on the object below this worm model, the screws aren’t snapping to the edge of the model for some reason.
Thanks.
For the first question, it can be a lot of different reasons: the base isn’t perfectly circular, the object isn’t aligned with the universe, etc.
Try to enable the Local Symmetry mode located in the Transform palette (L.Sym) and see if it changes something.
For your second question, it’s because you may have two ZSpheres on the top of each other, like you did a Shift+click on the top ZSphere. Pressing shift recreate a sphere of the same size as the previous one.
Local sym worked. Thank you. 
OK, glad to know 
