Apple Motion 5.1.1 - Manual (Page 496)

Chapter 13 Keying 496
Light Wrap controls
Click the disclosure triangle in the Light Wrap row to reveal controls for blending color and
lightness values from the background layer of your composite with the keyed foreground
layer. Using these controls, you can simulate the interaction of environmental lighting with the
keyed subject, making it appear as if background light wraps around the edges of a subject.
In the following image on the right, with Light Wrap applied, environmental lighting from the
orange sky background layer “wraps around” the edges of the candle and the right edge of the
woman’s hair.
Without Light Wrap With Light Wrap
In Motion, the Light Wrap operation blends light and dark values from the background with the
edges of the keyed foreground subject, and can be used to create color mixing effects around
the edges of the solid part of a key to better marry the background and foreground layers of
your keyed composite.
Light Wrap is the last operation in the image-processing pipeline. In other words, the light-
wrap effect is added after every other image operation is processed, including filters, lights
and shading, and other composited effects. As a result, Light Wrap properly accounts for any
other visual effect that might alter the look of the object it is applied to, yielding the most
desirable result.
Important: If the layer is set to the Light Wrap blend mode and you increase the Light Wrap
parameter in the Keyer filter above 0, the Light Wrap parameters of the Keyer filter take
precedence (and the Blend Mode is ignored). However, the Light Wrap blend mode in the
Properties Inspector for a group overrides the Light Wrap parameters of any Keyer filters applied
to layers in that group.
The Light Wrap group contains the following controls:
•
Amount: Use this slider to control the overall light-wrap effect, setting how far into the
foreground the light wrap extends.
•
Intensity: Use this slider to adjust gamma levels to lighten or darken the interaction of
wrapped edge values with the keyed foreground subject.
•
Opacity: Use this slider to fade the light wrap effect up or down.
•
Mode: Use this pop-up menu to choose the compositing method that blends the sampled
background values with the edges of the keyed subject. There are five modes:
•
Normal: Evenly blends light and dark values from the background layer with the edges of
the keyed foreground layer.
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