Easiest way to make an oval that matches curvature of two inner circles?

Rhino Rhino for Windows
1

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I’d like to generate the two interior blue ovals such that:

  • The curvature flows perfectly from the smaller inner circles (NOT SATISFIED)
  • While also just touching the perpendicular sets of inner circles (CURRENTLY SATISFIED)

I’m not actually sure if that’s geometrically possible or not, but if it is…what command might I use for this?

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Hello - you won’t get an ellpise that does this but BlendCrv may get you what you want.

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You’ll need to mark the circles with the desired blend locations so you can snap to these and get the thing symmetrical.

-Pascal

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Hi @RTK,

If you want a true ellipse that touches the four circles but does not cross any of them, then the diameter of the small circles must be less than or equal to one quarter of the large circle diameter (meaning that the minor axis of the ellipse has to be greater than or equal to half the large circle diameter).

Here, the red geometry is the edge case and the white geometry is slightly outside it. Red has one intersection with an end circle, white has three, meaning the lines cross:

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HTH
Jeremy

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Oval is a bit of an ambiguous term.
If what you want is the shape made up of 4 tangent arcs, you could use Curve>Arc>Tangent to Curves
then split the circles at these tangent points and join them together.
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