I am trying to use the graduated example in the Ten Second Tips in my scene, but somehow it's not working. I have a feeling it is to do with the expression. In your 10 sec tip, the expression written in blue is different from that in the screengrab below it. I have tried to use both with no luck - my tiles render black. However if I use a standard Material node without exporting any parameters the different materials show up..albeit not graduated. Please see screengrabs attached.
I'm sure it's something very simple but I can't seem to get it right.