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The RenderMan Interface - Paul Bourke

The RenderMan Interface - Paul Bourke

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Multiple calls to RiClippingPlane will establish multiple clipping planes.<br />

RIB BINDING<br />

ClippingPlane x y z nx ny nz<br />

EXAMPLE<br />

ClippingPlane 3 0 0 0 0 -1<br />

SEE ALSO<br />

RiClipping<br />

RiDepthOfField ( RtFloat fstop, RtFloat focallength, RtFloat focaldistance )<br />

focaldistance sets the distance along the direction of view at which objects will be in<br />

focus. focallength sets the focal length of the camera. <strong>The</strong>se two parameters should<br />

have the units of distance along the view direction in camera coordinates. fstop, or<br />

aperture number, determines the lens diameter:<br />

lensdiameter = focallength<br />

fstop<br />

If fstop is RI INFINITY, a pin-hole camera is used and depth of field is effectively<br />

turned off. If the Depth of Field capability is not supported by a particular implementation,<br />

a pin-hole camera model is always used.<br />

If depth of field is turned on, points at a particular depth will not image to a single<br />

point on the view plane but rather a circle. This circle is called the circle of confusion.<br />

<strong>The</strong> diameter of this circle is equal to<br />

C = focallength<br />

fstop<br />

focaldistance · focallength<br />

·<br />

focaldistance − focallength ·<br />

1<br />

∣depth − 1<br />

focaldistance ∣<br />

Note that there is a redundancy in the focal length as specified in this procedure and<br />

the one implied by RiProjection.<br />

RIB BINDING<br />

DepthOfField fstop focallength focaldistance<br />

DepthOfField -<br />

<strong>The</strong> second form specifies a pin-hole camera with infinite fstop, for which the focallength<br />

and focaldistance parameters are meaningless.<br />

EXAMPLE<br />

DepthOfField 22 45 1200<br />

SEE ALSO<br />

RiProjection<br />

RiShutter ( RtFloat min, RtFloat max )<br />

27

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