Specular map for a material with both metallic and non-metallic parts


I can’t get the hang of specular maps in Unity 5.

I made a barrel and I only want the metal straps to be reflective. I made a map which left the strap part of the uv light gray, but made all the wooden parts black. For some reason the entire model is reflective. I looked very closely at the viking village barrel and I can’t see where I’m going wrong. Any suggestions?

Thanks for reading.


View this video. Everything is explained here.