make glowing in the dark more realistic

Question

I'm making a glow in the dark cube. I think I figured out the best way to make the cube glow and animate the values change when the light goes out. But I'm wondering if there is a tip for making the internal not glow so much and fade darker inside the cube. As you can see from the first image this is a real cube, and you can see between the pieces it gets dark. But my model emits at the same level all around. So should I just assign a different emission to the faces on the inside of the cube and just emit at a darker color, or is there a better way to fade the emission darker inside the cube.

Real cube

my model

I lower the value for the mix shader when I need the cube to glow in the dark, and raise it back when the light in the room animates on again.

UPDATE: I didn't have any other angle of the real Rubik cube till today to show what I'm trying to do. The new image is what I'm trying to show. Inside the pink circles, I'm showing that the glow fades darker. And that happens on every face of the Rubik cube. How can I make the same effect to only fade darker on the faces that are on the inside of the Rubik cube. Each piece on the cube has the same material, so do I have to make the faces on the inside a different material and somehow make the glow fade dark separately from the outside faces of the Rubik cube.

Answer 1

Even though I am not sure where the effect on the real cube comes from, you can create a shader with variable emission across the surface using some Vector Math nodes.

Assuming the object center is in the middle of your cube. If your cube is larger than 2 units you need to throw in some scaling before the ColorRamp.

Basically we are computing a Manhattan distance from the object center, which fits for a cube. For spherical object the Euclidian distance would be the right fit, which is much easier to compute in a Blender shader tree, as shown.