How to solve the pinching in this concave geometry?

I have been trying to solve this type of geometry (a smooth "rounded" mesh with a concave edge at the top - as shown in the image). Any suggestions on resolving this, without getting the bulge at the side of the edge?

• Experiment with Edge Crease (Shift+E) that controls how closely subsurf modified surfaces follow edge corners. Mar 22, 2018 at 13:21
• You can use guide mesh as described here: blender.stackexchange.com/questions/96342/… Mar 22, 2018 at 13:57
• This seems like something that should have been solved by now. It seems all the "solutions" still have drawbacks. There are literally hundreds of this same question all over the internet. I think the default behavior should be a nice curve that follows the rest of the topology. And if you want the "pinched" look, you should have to specify so. I can't think of many scenarios where anyone would want to have an out of place pinch bulging out of their nice curve. Feb 4, 2019 at 0:51

As suggested in the comments, you can use a 'guide mesh' that the vertices of your object can snap to. The guide mesh is a simplified version of your object that describes the curvature that your original object should take. This works because some close-together edge loops not conforming to the curvature of the overall surface, creating a pinching effect. A guide mesh will force all vertices to perfectly match a surface.

I have created a guide mesh by adding a plane with a few subdivisions with a Simple Deform modifier set to 'bend' on it. You don't need to use a Simple Deform modifier, I just did this to get a perfect curved plane. It also has a Subsurf modifier before it to give the Simple Deform modifier more geometry to work with, meaning a smoother bend:

I then add a Shrinkwrap modifier to your original object and choose the simplified object I just made as the 'Target':

This does improve the result - the original object is now being clamped to the smooth, simplified object, however, we can improve the result by improving the topology of your original mesh.

Here we see some improved topology:

The further apart, or more evenly, your edge loops are placed the smoother your mesh will be, however, you obviously need some edge loops to be close together to create that sharp corner. The green markings in the image show that the edges near the bottom have been spread out whilst the red ones at the top have remained close. The orange markings show edges that have been partially spread out so that the change is more gradual. This gives us the best of both worlds, close edge loops where needed, but spread out where not.

I used the add-on 'LoopTools' add-on (which comes with Blender) as it has a 'Space' option (W> 'LoopTools'> 'Space') to evenly space out selected edges. On some edges I reduced the space 'Influence' in the 'Toolshelf' so they were only partially spread out.

This gives us this result:

You will notice some slight creasing still where that 'diamond' face is on the other sharpened corner, so you could use the same technique of spreading edge loops on this part of the mesh too instead of the 'diamond' technique.

Now, obviously, this was done on a flat mesh, whereas your mesh has some thickness to it. The solution to this is to either:

• Add a Solidify modifier after the Subsurf modifier.
• Use a second simplified object for the inside part of the mesh and use vertex groups to assign which modifier should effect which vertices.
• Apply the Shrinkwrap modifier and extrude normally.
• I was hoping for a "conventional" modeling way. (clever placement of proximity loops or something) Was hoping shrinkwrap was not needed. PS congrats on 20K rep. Mar 22, 2018 at 16:25
• @David Thanks. The re-positioning of the loops could be all that's needed if you want to spend a bit of time manually matching the loops to the curvature, the Shrinkwrap just automates that part. Personally, the Shrinkwrap modifer has become my conventional way of working because I don't think there's a better way. Mar 22, 2018 at 16:30
• @RayMairlot I've learned this method a while ago and I'm pretty sure it was from your blog, am I right? With Iron Man armor? I'm using it like crazy from that day :) Mar 22, 2018 at 16:43
• @LukeD Yes, that was my blog post. Glad to hear it was useful. Mar 22, 2018 at 16:53