# How can I bevel geometry that approximates a curve?

Consider a mesh like this:

This one is created by bisecting a sphere with some planes and then carving out another sphere out of it with the Boolean operator, but for the purposes of this question, any "curved" mesh will do.

How can I bevel the "curvy" edges of such a mesh? It consists of many faces and edges (because of the sphere geometry), but even if I select all those edges individually (see below) and then try to apply beveling only to those edges, the result is a huge mess. It either "stops at the next nearest edge" (best case) or produces a broken geometry. For more complex shapes, the result is really really bad.

I understand why this happens; for Blender, this mesh is not a set of "4 flat faces and 2 curved faces", it's a set of many small, flat faces, past which beveling doesn't really work.

I can, of course, bevel things manually by doing something like... create a torus that would just barely touch the mesh along two of its "faces", then create a cylinder from which the torus would carve out a chunk with a Boolean operator, then Bool that "beveling object" out of my mesh. All of this requires a massive amount of precise calculations with trigonometry. I've done this before when I absolutely had to, and it's not fun. Below you can see a quick illustration of this "manual beveling" process (ignore the slight mesh imperfection in the last image, I made a typo in the exact coordinate during one of the steps).

Is there a way to do such beveling (of "curved edges", not flat ones!) with a few clicks?

I've searched extensively for things like "beveling an already curved object" and so on, but it wasn't fruitful.

– user1853
Commented Jun 27, 2017 at 4:30
• @cegaton Sure thing, here you go: sendspace.com/file/uf79rx Commented Jun 27, 2017 at 4:50
• I think if your shape's geometry was a little more even, it would work. I just created a shape that's nearly identical and it worked perfectly. The "auto-options" like beveling work under the assumption that you've done your diligence to supply the necessary input. They are, after all, simply functions in a program that are designed with specific circumstances in mind. Commented Jun 27, 2017 at 4:53
• That being said, the circumstance will arise at some point where the shape dictates a certain geometry on which beveling cannot properly operate. Commented Jun 27, 2017 at 4:57
• @bertmoog There's nothing really wrong with my mesh; you got lucky with yours if all sorts of beveling work on yours. Consider this line of edges: i.imgur.com/Ho1HBN6.png - when I bevel those edges up above (the ones I actually need to), the beveling doesn't go below this "level". And I can't have control over these kinds of things in the mesh, especially not in more complex meshes than this one. Imagine that this "line" of edges was even closer to the top; then there would be even less room for beveling. I understand why all this happens, but I'm wondering if there's a workaround. Commented Jun 27, 2017 at 4:58

The auto-bevel option actually works better with less geometry. I know you said there's nothing wrong with your mesh and there's not in the strictest sense. But if you know ahead of time that you're going to bevel, you can make accommodations to that end in your design before you ever begin to construct the mesh. Still, it's easy to get this particular mesh prepared for auto-bevel by dissolving some edges:

The more edges you dissolve, the bigger the bevel can be:

But like I said before, there may be times where beveling fails to meet your needs or maybe it's an afterthought. Here's an alternative that I mentioned using proportional editing.

If you want to do just one corner:

Top and bottom sets of corners: I ended up adding geometry to the bordering faces and I applied some subdivision and shading... and now you have a Claymore:

These are just some ideas that I thought might help but there's certainly no substitute for planning and design.

• Ah, I get it now. The idea with dissolving some of the surrounding edges never crossed my mind for some reason. I agree that it won't always be possible to do this in complex geometry, but this will do for most of my purposes. Thank you! Commented Jun 27, 2017 at 20:09

All you need to do is remove this stray vertex here (merge the vertex with the one above it and dissolve the edge) to make all sides edge-loops.

Then everything bevels beautifully.

• "Then everything bevels beautifully." - well, somewhat beautifully, because there's still a limit to the beveling imposed by that other line of edges below the one I need (as shown in one of my screenshots in the post). But thanks for the idea about dissolving that edge! I wasn't aware of this technique before. As the other answer here showed, dissolving also helps you get rid of those other lines of edges that were in the way. Commented Jun 27, 2017 at 20:11