MATLAB® Graphics supports both orthographic and perspective projection types for displaying 3-D graphics. The one you select depends on the type of graphics you are displaying:
orthographic projects the viewing volume as a rectangular parallelepiped (i.e.,
a box whose opposite sides are parallel). Relative distance from the
camera does not affect the size of objects. This projection type is
useful when it is important to maintain the actual size of objects
and the angles between objects.
perspective projects the viewing volume as the frustum of a pyramid
(a pyramid whose apex has been cut off parallel to the base). Distance
causes foreshortening; objects further from the camera appear smaller.
This projection type is useful when you want to display realistic
views of real objects.
By default, MATLAB displays objects using orthographic
projection. You can set the projection type using the
These pictures show a drawing of a dump truck (created with
and a surface plot of a mathematical function, both using orthographic
If you measure the width of the front and rear faces of the box enclosing the dump truck, you'll see they are the same size. This picture looks unnatural because it lacks the apparent perspective you see when looking at real objects with depth. On the other hand, the surface plot accurately indicates the values of the function within rectangular space.
Now look at the same graphics objects with perspective added. The dump truck looks more natural because portions of the truck that are farther from the viewer appear smaller. This projection mimics the way human vision works. The surface plot, on the other hand, looks distorted.
By default, MATLAB adjusts the
CameraViewAngle properties to point the camera
at the center of the scene and to include all graphics objects in
the axes. If you position the camera so that there are graphics objects
behind the camera, the scene displayed can be affected by both the
and the figure
Renderer property. The following summarizes
the interactions between projection type and
All objects are displayed regardless of
Not recommended if graphics objects are behind the
Painters rendering method is less suited to moving the camera in 3-D space because MATLAB does not clip along the viewing axis. Orthographic projection in painters method results in all objects contained in the scene being visible regardless of the camera position.
The same effects described in the previous section occur in
hardcopy output. You should specify opengl printing explicitly to
obtain the results displayed on the screen (use the -