Hi Andrei,

> If I understand right, moi make base fillet surface than offset it and make trim?

No, the offset happens on the already existing surfaces on either side of the edge that's being targeted.

Like this:



Putting in a fillet of radius = 4 :



That means offsets like this:




The "rails" for chamfers are done in this exact same way as for fillets, it's just that instead of a rounded piece put in, a straight line is put in instead. When you use 2 chamfer distances it means each of those lines shown above uses its own separate offset distance rather than them both using the same one.

- Michael