All the materials we import from SketchUp are instances of a master Material that you’ll find in the Datasmith Content plugin. We created this master material to carry over all the material properties we can read from SketchUp, and interpret them to work with UE4. Using Material Instances is good, as Ken says above, because it avoids spending time recompiling the shader every time you want to modify a property. If you want to modify the node graph of the master material, you can do that too. You just have to create a copy of the master Material we supply, and set the Material Instance created by the Datasmith importer to point to your copy as its master.