Constrain circles into circles

roland_koeckel

Hello

I need to constrain circles into circles.

The diameter of the smaller circles is given put the position can be arbitrary.
The diameter of the bigger circles needs to be defined by the position of the small circles.
The small circles should always be within the bigger outer and inner circle.
The small circle closest to the center point should be tangend to the bigger inner circle
The small circle further away from the center point should be tangend to the bigger outer circle
Can this be done only with construction geometry and constrains?

https://cad.onshape.com/documents/349d77b05485db820938a6f5/w/dc3f9c2818549fe069a0f467/e/0e74713bf67de9a72314838e

dirk_van_der_vaart

This is what you mean?
https://cad.onshape.com/documents/1ed08e5cd28c81f52a9de89b/w/404af15de8ff567759618c78/e/fc8caa4955f6d3475e246873

roland_koeckel

@dirk_van_der_vaart
Thanks for your comment. Unfortunately this is not what I mean. There should be no hard dimensions for the bigger circles. These dimensions should be defined by the position and dimensions of the small circles. The inner circle should be tangent to the small circle that is more close to the center point. The outer circle should be tangent to the small circle that is further away from the center point

S1mon

This is either a really simple problem, or there's something else that you want that is not clear. I just added two tangent relations to your sketch. If you constrain the centers of the larger two circles (which you already did to the origin) and you constrain the location and diameters of the small circles (currently 15 and 16mm diam), then the sketch would be fully constrained.

steve_shubin

You start off by saying you want circles constrained into circles. You said you did not want the big circles to have dimensions themselves, but you did want them to be defined by the smaller circles . And you talked about position.

So I interpret this as if you’re wanting a fully constrained sketch where all the lines are black. Yet everything is adjustable. But no radius or diameter dimensions on the big circles themselves

You wanted to do it with only constraints. So it should be realized that dimensions are considered constraints

In the document below, adjust any of the dimensions including the angular dimensions to see if this is what you were looking for

https://cad.onshape.com/documents/d5d6c16164206bace26142a3/w/c47ba48aa660fbb606802be5/e/ef1ebce6ae965ffa5d7edd4d