Solidify modifier material Index offset not working So I read in the blender manual and watched some tutorials where it is explained that the material index offset is used to choose a different material for the new geometry. Alright this is the screen shot and what I'm trying to do is making a spaceship that glows from the inside and I cannot figure out how to change the inside color with solidify modifier, and I'm new to blender so sorry if this question is a stupid one. 

Here is the screen shot:
No stupid question. The answer to it is just obvious, if you know it. I struggled with it myself.  :)

Just add another material to your object. In your screenshot it's not visible, if you did this already. The index for Material Index Offset inside your Solidify modifier points to the position of your material in the material list.



So, if you leave Material Index Offset at 0, the newly generated faces will use the same material as the original object - the topmost material in your list. Set it to 1, and all original faces will use original material, while all new faces will use the next material in your list. Same goes for the rim - give it an own material as needed.