Lesson4.RotoShape

Lesson 4. RotoShape

Lesson Files	APTS_Shake > Lessons > Lesson04
Media	woman.1-70.iff
	laser.1-70.iff
	woman_roto.shk
Time	This lesson takes approximately 2 hours to complete.
Goals	Draw and animate spline-based shapes
	Navigate the various functions of the RotoShape node
	Create multiple rotoshapes for a walking person
	Use the MultiLayer node to combine multiple shapes
	Add motion blur to create photorealistic shape animations

A rotoscope is a mechanical device that was patented by Max Fleischer in 1917. It projected single frames of live-action footage onto an animator's drawing board. By simply tracing the projected shape, the animator could quickly produce incredibly lifelike drawings. With the passage of time, rotoscoping (or "roto" for short) has become a generic term for manually extracting, isolating, or affecting a portion of an image. It is tedious work, but it's one of the most important parts of the visual effects process.

Shapes are often created on a frame-by-frame basis to extract or isolate a portion of the image. Shake's RotoShape node can create multiple spline-based shapes that can then be fed in as an alpha channel for an element, or used to mask a layer or an effect.

RotoShape has many convenient features:

• You can create multiple shapes within the same node.

• You can have a soft-edge falloff that can be modified on a knot-by-knot basis for each shape.

• You can make one shape cut a hole into another.

• When you break tangents, they remain at the angle at which you leave them until you modify them again.

Note

In Shake 4.0 the black holes feature does not punch a hole in a rotoshape's alpha mask. Therefore, if you are using this as a mask, either use one of the RGB channels as the mask or reorder the luminance into the alpha when you use it with Inside or Outside. You can do this with Reorderrgbl or a LumaKey at the default settings.