The Compositor (blender Guide)

Hi.
You may have visited my other guide about Making a Minecraft Render in Blender
If you followed this tutorial you may come to a point where you are stuck with poor lighting
In this thread you will find out how to let things glow and also add an atmosphere which is better to look at by using the compositor
(tagging @yotamdin in advance)
Using -Blender Cycles version 2.77

As I said, following my old guide will lead to something like this:

this is bad lighting
If you have lamps in your scene, remove them, they are not helpful for anything.
Select those objects that emit light, in this case, I have sea lanterns
and go back to the materials panel and click that "+" you see in the bar

go back into the node editor, delete the Diffuse node and add an Emission shader:

You can change the amount of emited light with the "Strenght"-value

This will be the result:

Now, select everything in your scene (pressing A until everything is orange) and duplicate everything with SHIFT + D
Right-click again and move everything into another layer (button M->select another layer)
Then go into that layer and select the sea lanterns (or whatever light sources you have)
Press CTRL + I to select everything but the lamps, and SHIFT + Right-click an object that does NOT emit light to make it the active,
add another material with "+" and remove every shader, the only thing that you add will be the shader "Holdout" :

Copy the material to others (clicking the upside-down triangle that is in the material panel and say "Copy material to others")
you will get something like this:

you have to determine which size you want the render to be, so if you are using a 100% size resolution, toggle that this way and then render the image I have just shown you in that size, you will need the final result of the holdout image later on.

Go back into the node editor and go into composite mode, also check both "Use nodes" and "Backdrop"

render your original scene again and copy the following node tree:

to add glow effects, do the following:

of corse you don't have to have the exact same values as I do, try to find the best ones yourself.
and finally, adding the atmosphere

(slight change)
And this is the final result:

If you have any questions, feel free to ask me. There are a few things that I don't necessarily recommend, but you can use them such as Glare, Math nodes to increase the amount of power or decrease it. Nevertheless I hope I helped you out, happy rendering!

 

Helpful! Very helpful