Just joined, hobby level

[Jonathan]

At first it looks like just simple sin/cos ... but if I may there's one thing I think you might be missing out? When using a ballnose cutter, unless the cutter is kept perpendicular to the finish part's surface (impossible on a bowl without 5-axis) the cutter will cut more material off than intended. That's because the cutter is not a point, it has a finite diameter and the outer edge will cut more from the surface. It gets worse as the surface is steeper. This diagram will hopefully make it obvious:



It's a fair bit more difficult to work out the co-ordinates for that...

[cncgcg]

Hi Jonathan,
Thanks for the reply,
Very illuminating about it having to be kept perpendicular to the surface (impossible without 5 axis, as you said). I'm hobby level as I said, but it would have been fun trying to write it.
I think my idea, having looked at what you wrote, would result in a stepping effect, is that right?.
Is Tan necessary to roughly accomplish what I'd hoped for or can this all be done using Sin Cos alone?. I'm not into Tan...
Regards
Gareth