Hi Andrei,

> Thank you very much for you explonation, now I understan it is offset from surface
> to radius point. And when I enter distance I enter that radius.

Yup, that's correct. For an entire fillet surface that "radius point" is a centerline path curve, and it's formed by calculating the intersection between the 2 offset surfaces.

Then chamfers are done in the exact same way, which is kind of unfortunate in some aspects because there would probably be easier to understand ways to control it. But it's standard for CAD programs to deal with chamfers in the same way as with fillets, just with a straight surface put in rather than an arc put in for the cross section shape.

- Michael