Lesson 3

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  • Generating elements within Nuke
  • The Tracker node and one point tracking
  • The Tracker node, 4 point tracking and the CornerPin node
  • Integrating a foreground element with a background

Content

In this lesson, Nuke's 2D tracker will be introduced. The Tracker is the simplest of Nuke's tracker nodes. Like all trackers, it serves to convert apparent motion within a movie clip into key framed animated motion. More info on Nuke's tracking tools is here.

  • As the output will be animated motion, Nuke's animation capability will also be reviewed. This will include an introduction to the following interface elements: The Timeline of the Viewer panel, the Dope Sheet and the Curve Editor
  • The following time nodes will also be reviewed: TimeClip, TimeOffset and FrameHold
  • Nuke's 2D tracker, and brief instructions on how to use it, are detailed in the Tracker page.

The assignment will also require that a flame be generated within Nuke. The ability of Nuke to generate simple effects is surprisingly powerful. Water, fire and smoke can all be made without needing to go to an external app. However, these are mostly of a simple nature and not so appropriate for close up or complex work. Below are a few examples of effects generated within Nuke:

Item Details
Candle Flame Made using Noise and IDistort
Fire made using the Noise node, smoke, fire and sparks are made (quiet a complex script)
Water made using the Noise node
Rainbows! Two ways to make a rainbow.
Radial ripples Introducing the Grid node
Motion graphics 1 The dumbest example of motion graphics you will ever see...
Motion graphics 2 ...unless you count this one.
Reflection in water A variance of the Water script, with a wobbly reflection added using an IDistort
Flocking Not a real flocking, but close enough: using Expressions!
TV Distortion Noise TV
Mist A soft edged mist made using a Minus Blend Mode
Rorscharch Just like in Watchmen

Assignment: tracker

The output of this assignment will be a short clip of a person walking through a dark space, holding a candle or a flaming torch. This will be a composite of shot footage and flame, which will be generated within Nuke. The flame script can be found in the section above.

The footage you will shoot yourself. It will be a test of how well you can plan a shot in observance of its VFX needs. In this instance, the things to remember are:

  • The flame will be attached to the candle or torch using a tracker. The tracker will only need to output translation information (i.e. vertical and horizontal movement). There should be clear and trackable information in the candle or torch body.
  • The figure should not be walking to quickly or jumping around. Such information will difficult to track.
  • The lighting should not be too dark or too light. Over and under exposed footage has too much 'dead' information. Remember, it is easy to make a medium exposed image seem like it was shot at night, using no more than a simple colour adjustment.
  • The lighting should be flat: without hard edged shadows. This will be suitable for a scene that is lit using flames.
  • The environment should be suggestive. Perhaps a cave, or a large empty house. Such a scene may be improvised from available locations.
  • The light from the flame will light the face of the figure. I will show you how to do this in class. One way of doing this will involve the CurveTool.
  • When linking things to the Tracker output, don't forget to check out how to link output.

In summery, your task is simple: shoot footage, track footage, composite an element over the footage. The difficult thing will be getting it to look good.

It will be advised to team up for this project: to take turns operating the camera. Your shooting partner may be the actor, or you may find someone to do the acting for you. Some people are good in front of the camera, some are not. A simple test shoot might help to distinguish between the two.

Assets

Assets for Lesson 3
Name Description Link
A 2D Track: One Point An example of a 2D Track using Nuke's Tracker node (a zipped Nuke script). One tracked point has been used. Download (50mb)
A 2D Track: Four Points An example of a 2D Track using Nuke's Tracker node (a zipped Nuke script). Four tracked points have been used. Download (200mb)