Physically Based Rendering, 3rd Edition

2.9: * Animating transformations

pbrt supports keyframe matrix animation for cameras and geometric primitives in the scene. Rather than just supplying a single transformation to place the corresponding object in the scene, the user may supply a number of keyframe transformations, each one associated with a particular point in time. This makes it possible for the camera to move and for objects in the scene to be moving during the time the simulated camera’s shutter is open. Figure 2.15 shows three spheres animated using keyframe matrix animation in pbrt.

Figure 2.15 Spinning Spheres. Three spheres, spinning at different rates using the transformation ...