Have you been reading the complaints?
The GameBase option with a single material is completely unusable due to eyelashes, which are supposed to be transparent, being merged with the opaque body material. The InstaLOD versions come with separate avatars and no transparency mask texture which also pretty much makes them unusable in a production game. Basically, the only workflow that works out of the box with CC3 is just exporting the character as is with dozens of textures and materials. The advertised new workflow is broken and is not Game Engine ready and everything else is basically the same thing you had in CC2.
Correct me if I'm wrong, but I've yet to see a tutorial on how to get a game base character with merged materials or InstaLOD character with hair look presentable in Unity, most likely because it's not doable at the moment. 

There are some limitations to using a single material when it comes to eyelashes but they can be overcome.

If you are working on a character that is going to be seen in close-ups, then you will be better using the multi-material option when converting to Game Base. This will resolve any eyelash issues. However, if your character is going to be an NPC who is only seen in the background, then you can use the single material option and then set the Alpha Cutoff for the body material to 1 in Unity so the eyelashes won't be seen. Alternatively, you can adjust slightly so they are just barely visible.


                                                                

Peter
Forum Administrator

www.reallusion.com

Thanks for the alpha cutoff suggestion, Peter, it actually works pretty well for background characters. 
Do you have any suggestions on how to deal with transparency in InstaLOD versions? Since there's considerable overhead when using multi-material characters, using lower LOD versions for background NPCs would make the most sense. However, changes in LOD are very noticeable due to the lack of transparent layers. 
In CC3 there's an opacity texture assigned to hair and clothing, so if InstaLOD could generate a merged opacity texture as well the issue could be easily solved with a custom shader.

There is still a lot of issues with the exporter, on the "keep original" option when you export with lod, you should still be able to do all kind of texture baking/ material merging etc, on the "original", you kan only do this with merge material option, but then you get no lod, this is a mess? Tools for prioritizing how the different material is weighted when baked, this very very important! Now the face that is the most important texture get smaller than the tongue whrn baked, thart is crazy,  the list of stuff lacking is infinite...