BASIC / Node Editor 101

This is NOT a post about Blender Compositing, Blender Material Node or Blender Particle Node. This blog post is simply an introduction note for those who are new with "node-based" environment in Blender: the Node Editor.

Blender has this Node Editor for a while now and it keeps getting more features. It used to be solely on Blender Compositing and Blender Material (not Cycles), but it continue to expand to Particles. -- Who knows what comes next?

Blender Compositing has been quite solid feature on Blender, even before Blender has a new UI (Blender 2.5x). You will be using Blender Node Editor whenever you are using:

• Blender Compositing
• Blender Texture Node -> this is related to Blender Internal Render Material Node, for Blender Cycles, there are already bunch of Texture Node to use.
• Blender Material Node (for Blender Internal Render and Blender Cycles)
• Blender Particle Node (coming soon, I believe, it is out there in the trunk if you want to check it)

Blender Texture Node for Blender Internal Renderer's Blender Material Node.

This Node Editor is really convenient visual way to create a network of re-usable pipeline in regards to Compositing, Texture, Material, Particles.

Instead of "stacking" like what you have been doing with Modifier Stacks (which mostly closely related to Modeling), inside Node Editor of Blender you will be connecting and disconnecting nodes to create complex network that does certain effects.

It is in the way some kind of visual framework that is procedural and non-destructive. All you need to worry are:

• what function each node does (create, modify, filter, view)
• parameters/properties of each node
• INPUT and OUTPUT from left to the right side
• how do we process values from one node to the next node (how the data flow from one node into another)

This kind of node-based workflow inside Blender is not unlike Maya or Houdini or Softimage ICE, or Nuke node-based tools. So, Node Editor of Blender is really powerful, thus it is also very open ended, meaning that you will continue to learn a lot of tricks on your own. You need to experiment with it. You need to check Blender Artist Forum and read about what other artists do with it.

You will be surprised by how many useful nodes already provided and continue being added by Blender developers.

Useful Hotkeys inside Node Editor

SHIFT+A = general Blender shorcut that is also a very quick way to create new node, you can also create new node by searching the name
LMB or RMB click is to select node
LMB drag from Output slot into Input slot = to connect one node into another.
G = to move around node as usual
A = toggle select all nodes or deselect all nodes
S = "resize" nodes, make nodes come closer or spread apart from each other
CTRL+MMB = zoom in and out

RMB drag = marquee select nodes
CTRL+LMB = cutting noodle/connection of node
SHIFT+LMB = Creating Rerouter node, or basically adding additional anchor point on noodle
H = toggle collapse of selected node

ALT+LMB = well, if you do this on a node, it will grab the node and detach it from any input and output connection

(well, you don't need to remember all the shortcuts, but the really useful ones I will list above)

In Blender Compositing environment, quick connecting output to Viewer node can be done using shortcut -> Hold CTRL+SHIFT and LMB click on of any Compositing nodes to connect into closest Viewer node. If you don't have Viewer node yet, it will automatically create one for you.

Checkbox Backdrop to view image result of Viewer node:
V = scale Viewer backdrop down
Alt+V = scale Viewer backdrop image up

Alt+MMB+drag  = move Viewer backdrop image

Viewer Node display the resulting processed image in the Backdrop.

Although typically inside Compositing Node Editor you have Render Layers connected into Composite node, you can completely ignore them and Input Image File and connect them output into Viewer node. 

Working with Group Node inside Node Editor

Group Node is pretty advanced feature that is added not long ago, basically enabling you to put complex network of nodes and turn it into a "single node". It is in the way, some kind of process to create your own useful nodes that can be easily re-used.

TAB = toggle collapse of node group
-> unfortunately this is very non intuitive hotkey (!), but you get used to TAB for collapsing very quickly

This is a very helpful video:
http://www.youtube.com/watch?v=Jk_Kk5yOYvA

Must See Website and Video Tutorials related to Blender Node Editor (Compositing, Material building, etc)

1. Sebastian Koenig video tutorial on Blender Compositing. This is rare video, there is no other video like this. It is created using old version of Blender, but still the concept of Compositing is carefully explained:
http://www.cmivfx.com/tutorials/view/255/Blender+3D+Compositing


2. Gottfried Hofmann explains a way to create Absorption Material for Blender Cycles: (brilliant tutorial)
http://blenderdiplom.com/index.php/en/tutorials/item/104-tutorial-absorption-in-cycles

3. Andrew Price aka Blender Guru is exceptionally good at Compositing and also at creating complex and detailed realistic scene in Blender. His kind of skill is usually for people that are very observant and it takes years of hard work. His tutorial is indeed very high quality and well prepared, but also pretty advanced and intense as always:
http://www.blenderguru.com/the-wow-factor/
http://www.blenderguru.com/videos/create-realistic-materials-with-cycles/

4. PhonyBone Blog - Blender Particle Nodes Development Blog
http://phonybone.planetblender.org/2012/05/04/video-update/

5.There are some great posts here closely looking at the development of Blender Node Editor:
http://code.blender.org/

6. Blender Particle Info Node (if you are using Blender Cycles and Blender Particles)
http://code.blender.org/index.php/2012/05/particle-info-node/

Now What

Go and explore Compositing, example of advance Material Cycles, and Blender Particle node. That is exactly what I am telling myself to do. Whenever I have a little more time, I like to concentrate on this too.

Don't try to understand it all at once, you simply can't. At the beginning, just understand the concept of node connecting first. If you feel mentally challenged, download yourself Houdini Master and dig into a totally Node-Based environment.
http://www.sidefx.com/

You see, these business of connecting nodes is HUGE. As easy as one can connect nodes together, this area is actually can become pretty complex, very quickly. So maybe you want to focus on Compositing and/or Blender Cycles Material node creation for now which are already pretty solid and production ready, don't worry about Particles Node yet, that one takes a different set of mind.

Take it easy, even that Compositing and Material building using nodes are pretty complex!

Perhaps check documentation or test yourself what each node can do. But more useful  is to see how nodes work together to create something useful.

Getting yourself familiar with Node Based workflow and it will be useful for what you are doing in the future, especially if you are wanting to do Compositing or VFX.