I did try Autogroup with UV. Didn’t seem to do anything.
Did your model actually have UV’s already? I remember reading that it was something you were going to get to at some point. If you did not make UV’s yet, try this to get the groups back….
1. Load your “groupless” model into ZBrush.
2. As long as it hasn’t been modified by dividing or deleting anything, import the “polygrouped” tool you saved out before. It will replace the ungrouped mesh with the grouped mesh and will still transfer to Daz Studio via GoZ.
3. I recommend, before you send it back to Daz Studio, that you use the UVMaster plugin in ZBrush to create some rudimentary UV’s so that this will not happen again. It’s not important that they are exactly the way you like at this point. Make sure you select the Polygroups option in UVMaster. This will separate all of your polygroups in the UV map it generates.
4. Import to Daz Studio via GoZ or whatever way you are using.
5. Export from Daz Studio. I always put this export on my desktop while I work so it’s easy to find. Export with settings: Daz Studio scale 100%, collect maps.
6. Open in UVMapper (free program, totally awesome). Now you can select each group that was created by hitting Ctrl-G (select by group) then assign to a material. Save the updated object.
7. Import the new object into Daz Studio. Now, whenever you send it back and forth to ZBrush, it already has UVs and ZBrush will be able to restore your polygroups via Autogroup with UV’s.
Hope I explained this well. I don’t have any of these programs open right now and was going by memory. Good luck! You can PM me anytime if you need specific help with any of this. I’ve been using ZBrush since version 1.23 about 11 years ago. I am “Slosh” on ZBrushCentral as well.