don@andante.UUCP (Don Mitchell) (08/05/90)
I agree that motion blur is not a panacea, but I think it must be an option. In synthetic animation, you face the same problems and trade-offs that a cinematographer faces. Turn down the shutter angle and get strobing and judder, or turn up the angle (i.e., increase the exposure duration) and get motion blur. The biggest problem occurs when the observer tracks a moving object with his eyes, making the image more-or-less stationary on his retina. Then motion blur looks very strange. On the other hand, show a humming bird hovering, and you better be doing motion blur! Its not a simple signal-processing problem. The visual response with and without tracking is complex. 24 frames per second (or even the 60 fields per second of video) is just too slow. Research has shown that even 120 frames per second is too slow to eliminate motion artifacts. I seem to recall a paper by one of the SMPTE folks stating that 300 fps may be required to achieve complete motion realism. I have personally seen the ill effects of motion blur in 60 frames per second (a noninterlaced HDTV system). Obviously, we cannot change frame rate standards, so you have to just do what every good cinematographer does: make an artistic judgement about blur versus judder, and try to avoid problem situations in your animation. You can do something in synthesized animation that is not possible with a real camera, and that is to blur some moving objects and not others.