How can I delete the mid edges of the curves in geometry nodes?

Question

I create a path and want to instantiate objects along the side parts of the path using Instance on Points. However, when I try to do this, all edges are converted to curves and not just the side parts. I would have to delete the middle edges of the curve to make it work the way I want.

This is the path I want to use:

This is how I am currently trying to solve this:

Along the curves marked here I want to instantiate the objects:

That is the result I am currently achieving:

Download file

Answer 1

OK, your question was a little confusing and the pictures honestly couldn't explain what your goal is.

But here is the solution:

Subdivide the Curve Line before you convert it into a mesh. Then mark the start point and the end point, so you can select the edges afterwards.

Then convert your curves with Curve to Mesh.

Since you marked the endpoints before, you can now use them as selection for Mesh to Curve, and remain: The side parts of your road as single curves.

You can then instantiate your objects on these as you wish.

_{(Blender 3.1+)}