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1224 Chapter 15: Lights and Cameras
Yo u c a n a l s o c h o o s e C a m e r a s f r o m t h e S e l e c t i o n
Filters list on the to olbar, and then click the target.
Rotate (p age 1–420) adjusts the orientation
of the camera object. This transform is most useful
with
free cameras (page 2–1215) .
You can’t rotate a Target camera about its local X
and Y axes, b ecause it is constrained to aim at its
target. U se Move to move the camera or its target.
Also, if you rotate a Target camera to a nearly
verticalposition,eitherupordown,theprogram
must flip the Camera view to prevent the up-vector
from b ecoming undefined. If you need a camera
to look vertically upward or downward, use a Free
camera.
InaCameraviewport,youcanalsousethe
navigation buttons (page 3–788) to adjust the
camera interactively. Some navigation buttons,
such as Dolly and Orbit actually move the camera
or its target.
Using Clipping Planes to Exclude
Geometry
Clipping planes let you exclude some of a scene’s
geometryandvieworrenderonlycertainportions
of the scene. Each camera objec t has a near and
a far clipping plane. Objects closer than the near
clipping plane or farther than the far clipping
planeareinvisibletothecamera.
Clipping planes are useful for rendering selected
portions of a scene that has a lot of complex
geometry. They can also help you create cutaway
views.
Left: Clipping plane excludes the foreground chair and the
front of the table.
Right: Clipping plane excludes the background chair and
the rear of the table.
Clipping plane settings are part of the camera’s
parameters (page 2–1218) . The location of each
clipping plane is measured along the camera’s line
of sight (its local Z axis) in the current units for
the scene.
You can set the near clipping plane close to the
camera s o that it doesn’t exclude any geometry,
and still use the far plane to exclude objects.
Similarly, you can set the far clipping plane far
enough from the camer a that it doesn’t exclude any
geometry, and st ill use the near plane to exclude
objects.
The near value is constrained to be less than the
far value.
If the clipping plane intersects an object, it cuts
through that object, creating a cutaway view. (How
much of the cutaway object is visible depends on
whether the object’s material is two-sided or not.)
You can also use clipping planes in non-camera
view ports. Simply right-click the viewport label
and choose
Viewport Clipping (p age 3–774) .
Wa rn in g: If you use the mental ray renderer (page
3–77)
, geometry outside the clipping planes might still
appear in renderings.