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1380 Chapter 15: Lights and Cameras
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 2–1373).Thelocationofeach
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 camera that it doesn’t exclude any
geometry, a nd sti ll use the near plane to exclude
objects.
Thenearvalueisconstrainedtobelessthanthe
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
viewports. Simply right-click the viewport label
and cho ose Viewport Clipping (page 3–731).
Wa rning: If you use the mental ray renderer (page 3–78),
geometry outside the clipping p lan es might still appear
in renderings.
Usi ng the H or izon t o M a tch
Per s pecti ve
The horizon of a scene is the edge of vision at
the height of the camera, parallel with the world
coordinate plane. You can view the horizon in
camera viewports.
Horizon line displayed in a camera viewport
A camera is level when it and its target are the
same height from the world coordinate plane. In
other words, the camera’s local Z axis is parallel
to the world plane. When the camera is level, the
horizon line is centered in the viewport. As the
camera ti lts up, the horizon line lowers; as it t i lts
down, the horizon line raises.
The horizon line control is in the camera’s
Parameters rollout (page 2–1373).
The horizon line can help you match the
perspective of your scene to the perspective of
a still image. In general, matching perspective
involves the following steps:
1. Display the horizon line. Use it to help you
adjust the camera and target so they are level.
2. Display the image in t he camera viewport. Use
Views > Viewpor t Background and choose
Files in the Background Source group.