Fusion 360. How to parametrically relate the diameter of a circle to two others?

Question

3D

There are two base circles whose diameter is not exactly known (may vary within + - 0.5 mm). It is necessary to draw a third in the middle between these circles and attach a lot of things to these three. I would not want to redo all this when specifying the diameters. Actually the question is how to bind the third circle so that it always has an average diameter between the two base ones when their diameter changes.

PS. In principle, the middle is not a circle, but a polygon.

Answer 1

You failed to clearly formulate the problem statement. What is given? Two circles by their centers and radii and the diameter of the third circle? And you need to find a suitable center of the third circle in order to get a tangent to the first two? Problem for school geometry. Read textbooks and write a program. In CAD programs (in particular, in AutoCAD) there is a command for constructing a tangent circle from two others.
And yes, you can indeed set two parametric bindings "tangent" and then all three circles will be rebuilt together.