Other than wood, metal, glass, a glowing box is a common material I often need in my rendered environments. I have tried different methods over the years and for a 4 sided glowing box/column I am going to reveal the method I currently use.This is not a set by step but an overview of my methods to create these materials.
I typically try to get 1 material to do all the work but for a glowing box not with a frame I go ahead and use 2 materials and 2 objects combined together to produce the following result.
Why two objects and not one? Yes I could use a composite, blend, or double sided material and I often do for glowing boxes in a frame. For a 360 column like this I find the 2 objects gives a softer diffuse edge that brings more depth to the column. Sometimes you can add a shell modifier on the object and use a double sided material and it gets close to this effect but that could add additional issues.
The Modeling: Pretty simple there is the outer column and an inner column.
Outer Column: is just a standard box divided by 5 vertically. I chambered the edges to get rid of that hard edge and a surface to catch the light. Then I selected the dividing line edges, extrude the edges to create a nice v grooves around the column.
The Inner Column: is just a slightly smaller standard box to the first column with no modifications.
Now for the Materials
Vray Material – White Glow
Outer Column: Is a frosted glass Material using the standard VrayMtl
Inner Column: Is a VrayLight Mtl with a gradient ramp box map as the color. Tiled vertical by 5.
Vray Material – Colored Glow
Outer Column: Is a frosted glass Material with a colored map for the diffuse color. Since I was doing a multi colored column I used a gradient ramp for the colored map. Note: I like vibrant colors so if you leave the diffuse white the color is just a bit washed out for my tastes.
Inner Column: Is Vray Light Material with a composite map using the same gradient ramp box map tiled by 5 as the white glow overlaying the color gradient map.
Vray Material – Vibrant Colored Glow
The only thing different from this material and the previous colored glow is that I added the composite colored map into the fog color slot at 80% of the frosted glass material. This is for if you really want the color to not get washed out but still show that it is back lighted. Just note that this will up your render time so you can decide if it is worth it.