What is the geometry beyond this drawing?

specifically how to get the arc tangent to both other circles ? ( the red one marked in the drawing ) which geometry topic should I look for?

this seems an useful guide…

I could easily be missing the entire point here,… but it seems to me that the dashed line you’ve drawn in is highlighting the intersection of the two larger construction circles.

…and so the two tangent markings you’ve made come from only one of the construction circles.

… with it’s second companion tangent only matching up with one of the little outside tensioning circles (for lack of better words).

In this sense there is no common arc for either of the two mid size circles to share a tangent with… BUT you may know this already… so I’m not sure if I’m just trying to clarify my own confusion here… or maybe my comments can add to something a little better than that. (??)

Take Care,


thanks for let me notice that! your right ,

I come up with this definition anyway…
circle tangent.gh (13.6 KB)

What I was looking for is to find a way to generate the yellow closed curve given 6 circles which radius can be modified

Don’t know if it holds water

20200706 Wrap Circles.gh (12.5 KB)


that’s cool…
I tried several ways of selecting the circles , the example you send me is really close to what I had in mind, just I wish to exclude the two little circle and include the bigger one , is that what pick and choose component does?

20200706 Wrap Circles_re.gh (12.1 KB)

Ah I haven’t figured out a simple way to make sure it works. I am going to look into it a little later.

thanks so far i get here, but definition is very messy…:{
20200706 Wrap Circles_re.gh (19.6 KB)