Understand shutter profiles

In the multiframe rendering API, the BeginRecording call allows you to specify how fast the camera shutter opens and closes. The speed of the camera shutter defines the so called “shutter profile”. The following image demonstrates how different shutter profiles affect the appearance of motion blur on a blue sphere moving from left to right.

In all cases, the speed of the sphere is the same. The only change is the shutter profile. The horizontal axis of the profile diagram corresponds to time, and the vertical axis corresponds to the openning of the shutter.

You can easily define the first three profiles without using an animation curve by setting the open, close parameters to (0,1), (1,1), and (0.25, 0.75) respectively. The last profile requires the use of an animation curve.

In this example, you can see that the slow open profile creates a motion trail appearance for the motion blur, which might be more desired for artists. Although, the smooth open and close profile creates smoother animations than the slow open or uniform profiles.