- An introduction to the history and technologies of digital VFX
- An introduction to premultiplication
- An introduction to Nuke and compositing
Compositing is the act of laying one image over another, and is key to the art of digital visual effects. In a compositing operation, an Alpha Channel is used to create the illusion of transparency. The process by which this is achieved is called Premultiplication.
The digital compositing application that this course will use is Nuke. During class, we shall make a simple composite using Nuke. We will be placing a foreground over a background. The interface elements that we will be looking at are:
- Project Settings: Here global project settings will be defined.
- Node Graph: This is where the action is. Nodes are arranged in a 'tree-form' manner: with Read nodes at the top, a Write node at the bottom and lots of other nodes between these points, all working their magic upon the footage.
- Viewer: Here is shown a preview of the composite. Its a surprisingly complex panel.
- Properties Bin: This is where the properties of the nodes are displayed. The properties bin itself is very simple, it is in the properties themselves that the complexity lays.
- Toolbar: This is where all the nodes live.
The main nodes we will look at are:
- Read: This will read in an image or movie file.
- Roto: This is for making 2D shapes. At its simplest, it is a bit like the pen tool in PS or Illustrator.
- Merge: This will layer the foreground over the background.
- Write: Using this, the result is written out to file.
- Multiply: A simple color correction node.
- Transform: This moves and scales things.
You are also advised to get to know Nuke through these marvelous introductory videos (produced by The Foundry, the company which makes Nuke): Nuke interface overview, Importing footage / elements, Constructing node networks. Additionally, through RMIT library you have access to Lynda.com training vids. I recommend checking out the first chapter of 'NUKE Essential Training' by Steve Wright.
Having done this, make a new composite. It should include a background merged over a foreground. Its In all your Nuke scripts in the first half of the course, you are to follow the house rules as described here. General best practice for Nuke scripts is described here.
|Premultiplication||Good and bad Premultiplication practice: demo with a simple script.||Download (3mb)|
|Slides||My talk on the history and practice of VFX||Powerpoint (150MB) Keynote (150MB)|
|Example Project Folder||A zipped project folder, described here.||Download (13MB)|