I’ll try my best to describe what I’m trying to do. For simplicity’s sake let’s say I have a cube and I want a gradient transparency, of a specific color, to run diagonally through it. Upper left is opaque and as the color travels down and to the lower right it becomes completely transparent. It’s important that the opaque area (at least) react to environmental conditions like other solid cubes around it, because I’ll need to align a solid cube to the opaque upper left side of the gradient cube seamlessly. I’m having a time trying to even find a thread that fits so I started this one so I really appreciate the help 
I hope you have lots of painful suffering in the afterlife as punishment for posting a help question in the News section. However, my answer would be to just UV unwrap it. Go to the side view in edit mode, select all, hit U and select “project from view.” This will give a direct top-to-bottom linear gradient to your object’s UVs.Now make a material and add a texture, select “Blend.” Map it to alpha, use a gradient, and on the material panel have it also go to the bottom.
Man, if I had a nickel for every time I thought that…
…that’s what I get for thinking I could multi-task, or thinking period. I do, however, appreciate the help very much…and don’t worry, if there is a hell, I’ve got my own walk in humidor with a lifetime supply of turds to smoke