I fully agree with Kanni3d & Klunk, both on methods explained and how these are standards when it comes to manually unwrap your UVs. Like, it's normal to spend more time on things that can't be automated. The RizomUV result is quite poor for two reasons : - center edges are messed up (=will need later…
It's a bit time consuming, but that's the nature of (unautomated) UVing in general. If you have those few actions hotkeyed (since this is a common thing to do to get nice uvs) it isn't so bad. Strange that it's deforming it that much after stitching though, perhaps the broken off circular piece needs to have a striaght…
@Kanni3d Yes, I guess you're right. Maybe Autodesk comes up with a solution for that at some point. Following other folk's suggestion, I could solve this problem in RizomUV, which worked quite nicely. The only manual part was selecting the edges I wanted to be straight, apply a Horizontal Constraint to them and then, press…