Rounding out 3D models

Looking for a hint or link to software or a method that I can use to round out a 3D model. My son wants a costume/toy piece to wear thats based off a superhero. Models of what he wants are available online, but they are action figure sized - when printed at that size, they look fine. If printed a lot larger, large enough to fit his wrist, it’s obvious that it’s not round at all. I’ve tried using the remesh and smooth tools in Meshmixer, but I am FAR from an expert in 3D modeling. Is there a tool/function someone is aware of that will help with this?

I mocked these up real quick in 123D Design. The one on the left is what the model looks like when blown up, very large polygons, obviously a 7 sided prisim. What I’d like to get it to approximate is on the right, a rounded look.

The object is a lot more complex than what I posted above, or I’d just recreate it, it curves out in the center, has other details I’d like to avoid recreating.

When I try to remesh it in meshmixer, I either lose the hard edge of the ‘inner bevel’ or the 7 sided prisim retains it’s own hard edges. There are other similar things he’d like me to make as well. Is there a tool in some software that will help with this, maybe something more automated than the method I am trying to use?

When I built the 3D scanner for the local Makespace to try out, I had a copy of meshlab that I used to smooth the point cloud data coming from the the Ciclop scanner. You could try it and see if it will fix the polygon roughness you have.