Making vegetation was the hardest part of the work. Not because I didn't know how to do it, but because I want to keep rendering times as low as possible and - simultaneously - freedom of camera movement - that's why I didn't want to use billboards. I'm just not sure what the final camera movement will be. Finally I used X-FROG for trees and shrubs, "Ivy generator" for ivy and ingenious plug-in "DPIT Nature Spirit" for grass and dry leaves. DPIT is a plug-in which gives possibility to "paint" (clone) plants and other objects on surfaces (by mouse or pen - which I used for dry leaves) or use bitmaps for this task (which I used for grass). Textures for plants were taken from XFROG.
When I started to make renderings with GI (some time ago), I was trying to find everything about it on the internet. And I found several articles about linear workflow. If you are interested in details, please look on the internet - there's a lot of materials on this topic. In the brief, the whole thing is about gamma. Monitor displays pictures with gamma 2,2 (1,8 for MAC), but the render engine works in linear scale (gamma=1,0). All you have to do to work in LWF is that you should give your rendered pictures and colours in linear scale. You can do that by adding gamma correction with parameter 0,455 (this means 1/2,2 - for PC). There's a lot of advantages when using LWF: light goes deeper in the scene, rendering is natural and physically correct, you don't have to worry about colour mapping. Of course you don't have to use LWF (you can use colour mapping, desaturation, contrast, etc), but for me it's the best and the easiest way to make correct renderings.
Below - quick comparison: In every rendering I've used the same materials and render settings. No lights (one of the spheres is illuminated).
On the left - linear workflow (Colour mapping - linear multiply, Dark multi: 1, Bright multi: 1, Gamma: 2,2)
In the middle - no linear workflow (Colour mapping - HSV Exponential, Dark multi: 3, Bright multi: 3, Gamma: 1) (too dark)
On the right - no linear workflow (Colour mapping - linear multiply, Dark multi: 1, Bright multi: 1, Gamma: 2,2) (light but colours are washed out)
Lighting and Rendering
I really don't know how this shot (it will last about 10 or maybe 20 seconds) will look between previous and the next one, that's why I decided to make a very natural, well-lighted render - without any mood. The reason is that I want to have a lot of possibilities when editing this final image. I can brighten it up or darken it down, I can make this picture look greenish or leave it as it is - with a brown shade. In the scene I used only one light - physical sun and physical sky. (For rendering I used Cinema4D and V-Ray)
Compositing and colour correction
As I said before I wanted this scene to look dirty, dusty, sun-baked. I had to use colour correction. I gave the picture a "coffee-cocoa" shade, I made the light and dark glow also, I "changed" the sky and...that's all.