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I am trying to make a continuous loop from a few arc curves but when I do a curve to mesh with a curve cicle, the end faces dont align. This example has two arcs but I actually want to do 10 or more.

enter image description here enter image description here enter image description here

Timaroberts
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Roel Deden
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  • Perhaps if you described your goal rather than your current approach we might be able to work out a better way to solve your problem? – Marty Fouts May 08 '22 at 22:58

4 Answers4

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As quellenform commented, multiple splines won't align, but you can recalculate the ends or even the entire thing.

The reason for the misalignment is that the direction used to generate a profile curve in a point of the main curve is the interpolated value from the two adjacent edges, but in the ends of the curve there is only a single edge.

If you or someone else wants a Geo Nodes to fillet a curve with a true arc, here's one I did:

Geometry Nodes arc fillet

Arc fillet custom node

Arc fillet no misalignment

Hulifier
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I love Hulifier's interpretation of my idea, but what I love even more are simple solutions:

Why would you calculate the angle of the ends when Blender has already done that for you?

This image shows four arcs that were extruded using Curve to Mesh:

enter image description here

After all, since we have all the necessary information in hand when creating the arc and the profile, all you have to do is the following:

  • Calculate the angle of one segment
  • Select the points of the mesh at the ends
  • Transfer the positions of the points of the second profile segment (because it already has the correct rotation)
  • Rotate the positions of the end points according to the angle of a segment

enter image description here

quellenform
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if i understood you right, you just want them to align, and not "one" curve, so you could just increase the resolution of your arc to a high number and the align pretty well:

enter image description here

Chris
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  • Yes it is better but not perfect. – Roel Deden May 09 '22 at 08:27
  • yes of course, because the arc will be divided into pieces (defined by resolution) and Blender calculates from that "piece" the angle so it had to be infinite to get a perfect right angle. But - just my opinion - if you make it high enough you won't see it in render...and you can push it really high... ;) just my opinion – Chris May 09 '22 at 08:30
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I suppose you could wheel out the ol' Curve Deform group (simplified a bit), and use it to deform a prism of an appropriate length, given arc-span and arc-radius, then rotate the whole thing to the start-angle:

enter image description here

Here used to demo with the fixed default resolutions illustrated above:

enter image description here

enter image description here

Robin Betts
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