Camera Shutter Opening

The shutteropening parameter in PrmanGlobalStatements provides control over the speed with which the shutter opens and closes. Its two arguments, a and b, are fractions of the shutter interval specified by shutterOpen and shutterClose. Over the first part of the shutter interval, from 0 to a, the shutter gradually admits more light; from a to b it is fully open; and from b to 1 it gradually closes. The rate of opening and closing is constant.

Switch the useConstantRate parameter to "No" to enable a non-constant rate of opening and closing. This adds To control shutter efficiency, there are eight more arguments for shutteropening, c1, c2, d1, d2, e1, e2, f1, and f2. The two points (c1,c2) and (d1,d2) specify the rate of the shutter opening motion as control points of a bezier curve between (0,0) and (a,1). Likewise, (e1,e2) and (f1,f2) specify the shutter closing as a bezier curve between (b,1) and (1,0). More detail is available in the Shutter documentation.