# Rounded cap on Curve with Geo Nodes

It seems so simple but I just can't seem to make this happen with Geo nodes.

Can anyone just create a curve, attach geo nodes to it, add depth, create rounded caps, and then add a simple controller that makes the curve go certain degrees around a point?

Got to chuck one in.. I'm not getting this flickering that's being discussed here? Or maybe I am?

I do have a couple of bugbears.. the normals are not perfectly matched, even after welding, because of uneven mesh density, I think. Also, the geometry matches only if there are an even number of segments around the minor circumference, and cap rings. You could put in some math to constrain to that.. but that would just be more nodes.

This shows the GN followed up with a Weld and Subdiv

(Blender 3.0b) Crits welcome.

• This is beautiful!! <3 Commented Nov 16, 2021 at 6:53
• Man ... I just tried re-creating this ... it took 15-20 minutes and I got almost nothing LOL ... I will have to download this fille and try to understand this magic Commented Nov 16, 2021 at 7:15
• I might be ignorant but so many of your nodes are missing fields ... did you remove these somehow? Like your math nodes for divide don't have a second input? Commented Nov 16, 2021 at 7:19
• @General_Iridium Yup.. I think I collapsed (Ctrl-H) too many of these nodes, to try and make a reasonably-sized tree for illustration. Especially the Curve to Points. (I should have left that open to show only 2 points are sampled.) I'm relying on anybody interested to download and crack those nodes open (Ctrl-H, again). Maybe I shouldn't.. I don't know, these trees can get very big, and hard to decipher from a picture alone, so I'm treating that like a sketch. Fire away.. happy to elaborate to answer questions, or make suggested improvements. Commented Nov 16, 2021 at 7:36
• I mean, I think you have a GREAT result here ... it is actually exactly what I was looking for. I think I was just a bit discouraged since as small of a node tree as this is it is still very hard for ME personally to follow... maybe just because GeoNodes is changing so quickly ... I have no idea how guys like you KNOW about these nodes ... let alone can implement them correctly in challenges. Really wonderful work ... just thinking what do i need to do to understand GeoNodes better. ( keep in mind this is someone who has been using Blender for a long time now ) Commented Nov 16, 2021 at 13:08

you can do it with this node setup (it is Blender 3.0b):

*** UPDATE ***

This "should be" the non-flickering version, which works with "half spheres", which were rotated depending on the start and end degree.

• Nice ! I was looking for a way to rotate the UV spheres depending on curve control points tangents to avoid flickering but no luck. (Also removing the unseen half-sphere could make the curve/sphere interface seamless) If the camera is not too zoomed in this solution does the trick though. Commented Nov 15, 2021 at 16:15
• thank you. Yes, it is by far not perfect. But it is a good starting point .... ;) Commented Nov 15, 2021 at 16:16
• Can you make this work with a full circle? Commented Nov 16, 2021 at 7:38

I'm very late to the party, but I saw a video featured here on BSE:

Youtube: The Simple Solution to Blender's Bezier Curve Problem

So I thought I'll share my solution. Similar to the one of Robin Betts:

It aligns correctly to the 3D splines:

It's important the 2nd Euler Align is X not Y:

However the smooth shading for the above setup FAILS!

To fix it, either Realize Instances and Merge By Distance:

Or for performance, capture vertex normals before cutting the sphere and use that in the shader:

If you can still see a seam on the caps, this is because the surface is smooth, but the curvature change isn't (next derivative of smoothness), I explain it more thoroughly (and how to further smooth it) here:

What is causing this stretched shading on the mesh and how can I fix it?

This very simple node setup allows having rounded caps on any curve. The idea is to use the start and end points of the curve and generate a sphere on them. The curve can also be animated with a "Trim Curve" Node.

• Hi thanks for the answer. Could you add a short textual description of the procedure and how it works, along with the image, rather than just post a screen shot, so your post can be indexed and searched for by future users. Commented Mar 18, 2022 at 19:00