The Ray Tracer Challenge

Motion Blur

Motion blur is the effect you see in photographs of a quickly moving object, where it appears blurred because it was in motion while the camera’s shutter was open. Not only can this draw a viewer’s attention, it can make your scenes more dynamic by adding a sense of action. A skilled artist can do this with just a few strokes of a pen, but for the rest of us, there’s motion blur, like this:

In ray tracing, you could simulate this effect by rendering your scene multiple times, moving one or more objects a bit in each frame, and then averaging all the frames together. Here’s another way, though: for each pixel of your image, cast multiple ...