Backround So I have been making lightsabers on blender for maybe a year and forever I have been looking for a darksaber material and never could find one so I said fine ill do it myself(insert thanos joke here) and did do it
About This is STRICTLY for cylindrical or soft edged objects. if you want to do one fro hard edges just assign a emission material to the part you want to glow..duh. I made this so that no matter what way you look at It theres always a glow. I set it up as a node group because it makes it easier for newbies and everyone else too.
Customization Scale, rotation, and emission strength are linked outside of node group. So is the detail but it only aplies to the musgrave and noise options. There are 4 options, Lightning, musgrave, noise and voroni. You will have to go into the node and connect the output of the texture wanted to the Color 2 of the mix node. And change the color ramp, mixing, and blend of the fracing layer weight to get the wanted size and amount of white.
Eevee I made this specifically for eevee because it has a good prerender bloom option, make sure in the Render properties you enable bloom or else you wont see it in the camera
Cycles While i made this for eevee you can aslo utilize it in cycles if wanted, you have to use a fog glow in the compostiting tab. I already have it set up to what I think looks the best but depending on what you use the material on you might have to tweek the settings, Its all set up you just have to go to the tab and click "use nodes".