Now this has been a chore.
For the last couple of days, I’ve been studying up on how to make trees, plants, grass, and whatever other type of foliage look as smooth and detailed as doing everything with pure geometry. You think it’d be easy, especially considering how often people do it with seemingly no problems whatsoever.
Unfortunately for me, I’m not one of those people. Every attempt I’ve made has been filled with failed experiments, and rough compromises to get the look I want. For reference, I’ve been using what I’ve learned from these two pages for my trees and shrubberies.
Airborn Trees
Blender Specific Tutorial For Spherical Normal Shaded Trees.
With that latter one, you’d think I’d knock it out of the park. Nope!
Here are my problems. On a two sided, non backface culled object, I can get the top halves of my trees looking decent. Unfortunately for me, the backfaces are almost always extra dark, no smooth gradient, and it stays that way no matter what I do. The Normal Edit modifier doesn’t seem to do much of anything with the sphere trick, and editing the coordinates manually can get me smooth shading, but I sacrifice accurate lighting.
I’ve tried turning on backface culling, duplicating the object, and flipping the normals. That nets me about the same results, and usually flips the faces back to their “proper” orientation when I run it through the modifier.
Now I’ve come close to getting what I want. When I turn on backface culling, and carefully position the bushes I’ve made, I can make it look good, so long as I look at it from one specific angle. The dark shades are properly dark, and the lights are all scene accurate. If I start rotating around it though, whole chunks of my object will disappear as I come across the rear faces. It’s such a tease, cuz I’m so close, but I need a technique that works reliably without spending 45 minutes just to get something that looks good only in specific circumstances.
…and of course this has run up against my black contour trick. I really do wish you could turn backface culling on per object, and/or per material. I found a technique for the latter, but it doesn’t seem to work in Eevee. Eh. I’m still learning. 
Here’s a shot I fixed up showing how things should look when they’re firing on all expected cylinders. The bushes look great right now, but if I turn off backface culling, they’re filled with tons of ugly blotches. The grass is all geometry, all three million polygons worth, cuz I can’t manage to make x-planed grass without it look like pureed butt.
Help me achieve my dreams of pretty foliage!
