This sounds fine to me, but either way I think changing the name to something other than vertex group would be a good idea because I feel without a tooltip I wasn’t sure what it did. I like the idea of being able to use an attribute, this feels like the most mature choice for the software, but vertex group for now is sufficient until we get attribute painting working on stuff other than colors.
As for the issue of how to bring up the options before unwrapping, using blenders conventions there are a couple ways to deal with this.
1:
In all honesty I’m a fan of the idea of putting changes into the UV editor, perhaps in the N panel like Dangry suggested.
This method would keep settings in the UV Editor preferably, or perhaps Scene. Changes in settings are linked to the operator in the 3D viewport. If you change it to slim from Angle based in the 3D viewport, the UV editors N panel does so as well and vice-versa. But this allows people to set settings in the UV editor, so when unwrap is ran from the 3D viewport it would be using those settings.
I like this method best because there is zero starting an unwrap you wouldn’t want. This makes even existing things like “margin” or “use subdivision surface” or “fill hole” etc, to not need a secondary unwrap. As well, there is no extra clicking associated with “unwrap”, it just unwraps. You could even make the UV editing workspace have the N panel open by default for discoverability.
Finally, it lays a groundwork to add new panels in the UV editor in the first place. Right now the UV editor is pretty baren and almost doesn’t feel like it deserved the split from the image editor back in the day. There is a pretty sizeable backlog of delicious confirmed tasks Daniel Bysted left for developers to tackle whenever, and some of them could potentially use panels.
Sorry I suppose this all might be off topic from SLIM but it seems like as good a time as any to bring it up.
2:
Just like batch rename we have a little pop up window before unwrapping. It’s not the best because it needs more clicks and people are already worried about that
Maybe another operator underneath unwrap like “unwrap advanced” could be implemented and just brings up the popup. Personally I don’t like this method as much.
3:
This is sort of alright, it would feel cleaner if we didn’t need to go through that in the first place though. As well, sometimes the unwrapping process on really complicated meshes basically takes up all the CPU and you can’t even interact with blender until the operation is finished.
No matter what happens, a progress bar that you are able to hit exit on to stop the operation would be extremely welcome!