# Ramp/helix along spheres

Hello! I’m having quite a difficult time ! I’m trying to make a ramp along the spheres, more or less like the red one and I have no idea how it could be done. I could use some help!!

Try this:
Make a sphere.
Use CreateUVCrv
It will unroll a rectangle near 0,0
Draw diagonal line across it so the end on one side is horizontal to the one above/below it.
Use ApplyCrv to put them back on the sphere.

Remember the top and bottom of the rectangle represent the zero length singularities of the sphere so the curve tighten up at the poles.

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Hi Cristina
Try the command InterpCrvOnSrf like the attached yoytbe movie.
Ciao Vittorio

I know this method but it doesn’t work on the boolean of more spheres, so that it could connect my spheres.

When I’m using ApplyCrv I’m asked the surface on which my crv should be applied on, but I can’t select both spheres, I can only apply it on one of them. I can’t connect both spheres through a spiral, even if they are connected by boolean.

Following is one method…

1. Create a helix around the outside of your objects
2. Loft between the helix and its axis line to create spiral surface
3. Intersect the spiral surface with the spheres
4. The resulting curve will be your spiral on the surface of the spheres.
5. Delete (or hide) the unneeded construction geometry.

Note the result will depend on where you place the helix axis relative to the objects… If you have History recording on, you can move the spiral surface around and see the result change.

–Mitch

SpiralOnSpheres.3dm (1.4 MB)

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That’s what I was looking for! Thank you!!