Grass Valley Karrera Video Production Center v.4.0 - Manual (Page 279)

KARRERA — User Manual 279
Corner Pinning
Corner Pinning
Corner Pinning allows you to move the corners of a source image relative
to the background. Corner Pinning is keyframeable, with all standard path
control functions. The new corner locations do not need to form a rectangle.
Corner Pinning is accomplished by distorting the source to fit into its newly
defined corners. The modified image remains in its original source plane,
and is not “bent” along the Z axis. Corner Pinning does not change the loca-
tion of the axis of rotation or spin of the source image (
Figure 150 ).
Figure 150. Corner Pinned Object
Corner Adjust Limits —Corner Pinning works for convex quadrilaterals but not
for concave quadrilaterals. A convex quadrilateral is defined as a four-
sided shape with all angles less than 180 degrees (
Figure 151 ), all vertices
point outwards and all diagonals lie entirely inside the quadrilateral.
Results from adjusting a corner beyond the limits are undefined.
Figure 151. Convex Quadrilateral—Corner Adjust Limits
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180 Degrees
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