There are gotcha’s in this latest main SL Viewer 3.8.4, in the mesh upload. You can use more than 8 materials now. Gaia Clary has changed AvaStar to export more than 8 materials. But, the announcement of that change comes with a warning: don’t.
Also Drongle McMahon commented on the problem and what happens when we exceed the allowable polygon limit per material for mesh items. See: Second Life’s Limits.
So, why does Gaia say don’t? Because the 9th material is split out into a separate linked object. I find that rather surprising. I also think it is a major addition to the learning curve. All this seems to run counter to the Lab’s normal criteria for changes and new features.
So, what is the point of having sixteen materials on an item in Blender if it imports to SL as 2 objects with 8 materials each? No one had offered a good reason.
Get Avastar-1.6-98_blender-2-70 if you want to try the 8+ material thing. I think this is an alpha version… If you are thinking about using it, you may want to get more information from the in-world support group.
There are other things happening too. See Drongle’s comment in the Knowledge Base. This one has to do with file naming changes for mesh uploads that come with this new viewer version. Gaia makes no mention of AvaStar is going to automatically create those names, I doubt it.