Create a quadratic bezier from vertices of three different circles in Geometry Nodes

Question

Im have three circles with the same resolution, and I was wondering how could I take a vertex from each circle and use it to create a quadratic bezier.

For example, take the first vertex of the three circles and make a quadratic bezier with the starting point, middle point and last point. Repeat that for every index.

I tried some different stuffs with the Transfer Attribute node, but the result is not what I was looking for.

This is what I achieved:

What I want is something like this:

These are my GeoNodes for it:

If I substitute the "Integer" node before the transfer attribute nodes for the "Index" node, it doesn't work.

Answer 1

You can achieve this relatively easily by simply querying a certain position of each of the three circles.

The easiest way to do this is to use the node Sample Curve. It will directly provide you with the required positions for your curve.

After you have created your curve, you have two options (depending on what you really want):

Method 1

You can rotate and instantiate with Instance on Points along one of the circles to get exactly the shape you sketched.

If you divide $\pi*2$ by the number of points, you get the angle for a stepwise rotation.

Method 2

You can also create a mesh directly from this profile curve by using the node Curve to Mesh.

...and of course you can also use this method and remove the superfluous horizontal edges afterwards.

Here is the blend file:

Answer 2

you can use this node setup:

to get this:

The quadratic bezierpath has 4 control points for its lowest resolution. So for 3 circles...you didn't define where the points should be. So i just set 2 points on the same spot.

And no, i won't change my answer if you want it another way (unfortunately i made this experience often here that people than "improve" their question to get what they really want, but i think the question shouldn't be changed but then they should ask a new more precise question)