Cameras
You must set the Viewport3D's
Camera property to one of the three
available camera types: PerspectiveCamera, OrthographicCamera, or MatrixCamera. The type of camera determines
how the 3D model will be turned into a 2D image on-screen.
The PerspectiveCamera is often
the most natural choice. With this camera, the farther away objects are,
the smaller they appear. Because that's how things look in real life,
this produces a reasonably natural-looking image.
The OrthographicCamera uses a
more simplistic approach. A 3D object of a particular size will always
be rendered at exactly the same size, regardless of how far away it is.
This tends to produce rather unnatural-looking images, but it can
occasionally be useful—sometimes consistency is more important than a
natural appearance. If you are rendering 3D models representing the
design of something physical, such as a planned piece of woodwork or the
layout of a room, you might want objects of the same size in the model
to appear the same size on-screen. Likewise, if you are producing a 3D
graph, consistency of size might be more important than realism. An
OrthographicCamera can guarantee
this, whereas a PerspectiveCamera
can, by design, show equal-size objects as different sizes on-screen.
Figure 17-1 shows an
example—on the left is a series of identical columns rendered with a
PerspectiveCamera, and on the right
is the same model as shown by an OrthographicCamera.
Figure 17-1. PerspectiveCamera and OrthographicCamera
If you are ...