I’m having a problem with clipbrushes on OSX.
first I have a problem with a lip or flask around the edge of a clip, doesn’t matter which brush.
Then I am having weird MIRROR problems on primitives, especially with the Radial symmetry.
Instead of 8 I get this weird mirror ever when Mirror is off. I get sixteen.
When I use the brush radius option I don’t seem to have a problem.
thanks. 
When using radial sym and a clip brush the reason your getting twice the number of expected ‘clips’ is because the clip brush is clipping all the way through the tool. It doesn’t seem to respect backface masking so you’ll probably have to apply a mask to prevent the unintended result. (I’m sure your aware but others might not be… the clipping brushes won’t cut a hole through a tool)
Is it possible that the lip/flask your getting is from using the inverse of the clip brush which will expand the clipped area to fill the clip shape?
Hope this is some help.
Sam
You have to remember that clip brushes don’t “cut away” geometry, they only push the polygons to conform to the shape your after. In the case of your sphere, you clipped below the center point of the sphere and as a result, all the polygons were pushed straight down to that point. The outside diameter of the ring you see is exactly the same diameter as your sphere. If you cliped above the center point of your sphere, you wouldn’t get the ring because the diameter of sphere would be smaller at that point. Hope this makes sense to you.
ZBer. You are absolutely correct. It’s so weird but it makes sense now. Even after you explained it, I still have to try it a few time before I got it to work, but now it works consistently. Thank you so much it was frustrating not being able to do such a seemingly simple operation.
And thank you Summer.
Zber can I asked for more help with the assymetry problem? or Maybe I can figure it out now that I am getting these basics a bit better?
Again thanks all for contributing to this solution.