Assets used in one UNIGINE project, both simple and composite (e.g. a material requiring a texture, or a node that requires several materials linked to plenty of textures), can be easily copied to another project using Asset Packages.
More on using Asset Packages in UNIGINE 2: https://l.unigine.com/peRZpLgsl
Download UNIGINE 2 SDK: https://l.unigine.com/X6CrCnaD1