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#!F-adobe-helvetica-medium-r-normal--18*
#!N
#!CDarkGreen
#!N #!Rprojmet Changing the Projection Method #!N #!EC #!N #!N Data
Explorer provides two methods of image projection. These methods make it
possible to map a three-dimensional image onto a 2-dimensional screen. The
two methods are: #!N #!I0 #!N #!N #!I0 #!N #!F-adobe-times-bold-r-normal--18* Perspective
#!EF #!I50 #!N Perspective projection simulates normal camera and human visual
systems, thereby providing realistic rendering of objects. While it is realistic,
it does not preserve the exact shape and measurements of the
object, and parallel lines usually do not project as being parallel.
#!N #!I0 #!N #!F-adobe-times-bold-r-normal--18* Orthographic #!EF #!I50 #!N Orthographic projection provides
a less realistic view of an object than perspective projection. However,
orthographic projection does preserve exact scale measurements and parallel lines. One
way to think about orthographic projection is that it is as
if the distance between the front and back of an object
is small, relative to the distance between the object and the
camera. Orthographic is the default projection method. It is quicker to
render an object in orthographic projection than in perspective. #!I0 #!N
#!N #!N #!N The differences between these two methods become evident
when using the view controls in certain modes. For example, the
#!F-adobe-times-bold-r-normal--18* Zoom #!EF mode behavior depends on the projection method, as
does the behavior of the 3-D cursor ( #!F-adobe-times-bold-r-normal--18* Roam #!EF
and #!F-adobe-times-bold-r-normal--18* Cursors #!EF modes). The differences are discussed in the
sections that discuss these modes. For more information about these projection
methods, consult a computer graphics text. #!N #!N You can select
the projection method by using the #!F-adobe-times-bold-r-normal--18* Projection #!EF option box
on the #!F-adobe-times-bold-r-normal--18* View Control... #!EF dialog box. #!N #!N #!N
#!F-adobe-times-medium-i-normal--18* Next Topic #!EF #!N #!N #!Ltall304,dxall304 h Setting the View Angle #!EL #!N #!F-adobe-times-medium-i-normal--18* #!N
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