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Viewing Volume
Viewing Volume
- See also: Concepts Of 3D Graphics, View Points
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- Viewing Volume is the part 3D space which is currently displayed in
the 3D View. Viewing Volume is a rectangular 3D box, four sides of which
are orthogonal to the plane of the screen and extensions of which intersect
plane of the screen at the screen edges. Dimensions of the Viewing Volume are
expressed relative to the Eye Frame.
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- Reducing
the Viewing Volume to contain only a particular object of the model is
equivalent to zooming in on the object. Everything else will be cut off.
Expanding the Viewing Volume allow to display more on the screen, which is some
sort of zoom out. All Viewing transformations like Zoom, Pan Rotate including
ones performed programmatically result in manipulations on size, position and
orientation of Viewing Volume. For example Pan (Translation) of the scene with
the mouse results in shifting the viewing volume in direction opposite to the
mouse movement.
Programmatically dimensions of the Viewing Volume can be accessed and
manipulated via ILook
interface. To manipulate its orientation its is needed to manipulate the
current Eye Frame (relatively to
the
Global Frame) or, inversely to manipulate the
Global Frame (relatively to the Eye Frame). See also
Viewing Interfaces.
Note that dimensions of the Viewing Volume in z direction (depth coordinate)
are always finite. If model falls out of the z extents of the Viewing Volume it
will appear clipped at furthest (dMin) or nearest (dMax) side of
the Viewing Volume. Z dimensions are important for rotations as it determines
location of center of the rotation, which coincides with center of Viewing
Volume.
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