PRG Mbox Designer Manual 3.9 - Manual (Page 105)

MBOX ® MEDIA SERVER USER MANUAL 97
Drawmode 16 - Orthographic View
Drawmode 16 causes 3D objects to be drawn using orthographic projection. Typically, when 3D objects are drawn in
Mbox, they all share one vanishing point, which is a fixed point at the center of the screen (assuming the camera is in
its default position). Because of this, any object that has depth will show some amount of perspective shift as it is
moved around the screen or as the camera moves. If the object is being used as a mask or to simulate a shifting piece
of scenery, then the perspective shift within Mbox may not match that of the actual object. This situation may arise
when using a projector. The degree to which the perspective shift causes issues will depend on many factors
including the type of projector used, the throw distance of the projector, the type of lens used, the amount of
movement of the object, and the object's depth.
To eliminate the perspective shift, command Mbox to draw an object using an orthographic projection mode. This will
cause the object to be drawn so that its vanishing point is always directly behind the object, no matter the position of
the object or the camera. In order to properly scale the object, this drawmode causes a section to be taken through
the object's center of depth. Due to the constraints of the modeling process, this mode only works well with rectilinear
objects which have one major face perpendicular to the camera.
The following illustration show an example of Drawmode 16:
The following illustration shows an example of when Drawmode 16 is not very useful:
A cube from the front, centered on
the screen The same cube positioned off the
center axis. Note the perspective
shift. The cube, off axis using Drawmode
16. Note that the cube appears to
be smaller. This is because the
section is taken through the center
of the object.
a pig using Drawmode 0 the same pig using Drawmode 16
(not useful)