Hi,

Is there something like Unreal engine's material instance in Solaris USD?

Thanks!

Specialize? I'm not familiar with what an Unreal material instance constitutes. You can make any kind of reference arc with material prims.

Just like HDA, the main material has inner nodes and also a common parameters interface about scalar, color, or texture names.
The instance only changes the parameter interface of the main material and can be assigned to prim as normal material.

You can try Edit Material Properties LOP with the "Reference Type" set to 'reference' or 'specialize'.