GRASS VALLEY zodiak, User Manual

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82 Zodiak User Manual
Section 2 — Concepts
Figure 55. Screen Coordinates
Screen units are also used to define Z axis dimension depth in 3-D space.
Positive Z axis values are back behind the picture, and negative values are
in front of the picture (
Figure 56 ).
Figure 56. Viewer Location in 3-D Space
For perspective calculations the factory default viewpoint places the
viewer -16.67 screen units from the monitor screen surface (4 x 3 aspect
ratio). In this case, moving a full screen image 16.67 screen units back
behind the screen makes the picture appear half its normal size to the
viewer.
Size
Picture size is defined relative to picture screen units. A size of 0.50 indi-
cates a picture is one-half its full size.
Rotation
Rotation is measured fractionally with respect to 360°. A value of 0.25 indi-
cates a rotation of 90 degrees; 0.50 indicates 180 degrees (maximum rota-
tion). Rotation values can be positive or negative, which determines the
direction of rotation.
0
+3Y
-3Y
+4X -4X
+9Y
-9Y
+16X
-16X
0
0
865
_
01
X
-Z
+Z
Target
Viewer
- 16.67 Screen Units
+ 16.67 Screen Units
0865_02
Source
Source