TYPE: Object State
TITLE: Camera Operation

The Camera operation is used to manipulate camera parameters interactively.
This operation allows you to move and orient your camera and modify focus 
and frustum parameters through the use of three handles.

ORIENTATION HANDLE

The Orientation Handle allows you to move and orient the camera by either
manipulating the camera origin or the focus point.  Two orientation manipulators
appear one centered at the camera origin and one centered at the focus.  Each
manipulator is made up of two components, a pivot and a vector.  The pivot
allows you to move the camera or focus point, and the vector allows you to
orient the camera.  By default, moving or orienting the camera pivot will keep 
the focus pivot fixed and vice-versa.  Disabling the vectors (by clicking on 
one of them) unlocks the origins so that the camera and focus move together.  
Enabling the vectors allows the camera and focus origins to move independently.

FOCUS HANDLE

The Focus Handle allows you to set the focus parameters for the camera.  The
focus point is shown as a box bead with two arrow beads on either side.  
Sliding these beads along the camera's view direction changes the corresponding
parameters for the camera.  The two arrows change the f-stop parameter.  They 
represent two points where the image will be twice as blurred as the focus.  
When snapping is turned on, these beads can be snapped to elements whose 
location will then be projected back onto the camera's view direction.

FRUSTUM HANDLE

The Frustum Handle allows you to modify the camera's view frustum parameters.
Sliding the two box beads on either side of the camera's view direction will
change the near and far clipping planes.  Adjusting the aperture (or 
orthowidth, if orthographic camera) can be done with the scale manipulator.

FRUSTUM CLIPPING

The Camera operation allows you to visualize certain parameters in the viewport.
By enabling Full Frustum Clipping, everything that is outside the viewing 
frustum will be displayed in the Template shading mode.  If your shading mode
is Flat Shading and your Template shading mode is Wireframe, for example, 
everything outside the camera's view will be drawn in wireframe.  Similarly,
by enabling Focus Frustum Clipping, everything that will have a blur factor
larger than 2.0 will be shaded with the Template shading mode.
