As a related question, I've been battling with this exact same issue, but my problem - I think - lies with user created generators, adjustments, filters etc I've been gathering from Substance Share (e.g. the brilliant 3D/4D simplex noise generator by rattle). Is there a way to use these nodes and still have a Unity-functional .sbsar file, or are people using for .sbsar workflows forever banished from using custom nodes?
The resulting errors unity-side are the same, but SD4 compatibility view does not give me any information as for the cause. It's rather hard to track down the culprits from the graphs...
This question might strike you as basic-level, but I only recently started using this software, and find being limited in nodes very frustrating. .sbsar is so incredibly powerful in unity!
Hi,
You should be able to use custom nodes you create. The generators should be working. The triplanar option doesn't work correctly in unity because it requires the GPU engine.
I'm sorry but you shouldn't really be limited in nodes. Can you post an example and can take a look at?
Cheers,
wes
After a bloody Battle of Understanding, I actually discovered the combination of reasons for most of my import failures. Ended up being a combination of known issues (normal atomic node default alpha to 1 setting, etc) After I sort out the mess I'll come back with one of the mats that still mysteriously don't work. 80% of the catastrophy has been averted though, luckily

Grunge maps from SD6 don't seem to import, for example.
[edit:] wes, sent you a dropbox link as PM