I’ve noticed that when things or characters move, they cannot stop sharply but always sorta “coast” a little, as if they had built up momentum and couldn’t stop. Why is this?
I’ll try to find examples if no one knows what I mean. I’ve seen this in movies like both Toy Story’s, Iron Giant, and kids’ TV programs (like Beast Wars). Although I saw Shrek, I didn’t see this movement problem, maybe because I was too involved to notice upon a first viewing or maybe because the problem has been fixed. I assume it is a problem and not a deliberate way to program movement to reflect reality. But maybe when CGIs stop moving suddenly, they look odd.
This both is and isn’t a problem. The little slide to a stop is deliberately programmed.
Convincing human/animal motion is difficult to replicate in computer graphics. The problem originally was that everyone would come to a hard stop (arms swinging abruptly stop, walking to an abrupt stop, etc.) It often looks as if the character ‘snapped’ into place.
So, to make things look better they programed the movement algorithm to be a bit fuzzy or softer. Instead of going from speed 10 to 0 the computer decelerates 10, 9, 8, 7…etc. Unfortunately this isn’t completely realistic either and shows as a glide to a stop.
The ability to convincingly animate objects has been continually improving. I haven’t seen Shrek but it certainly represents state-of-the-art today which is much better than Toy Story (whose quality can now nearly be rendered in real time on a top-of-the-line desktop PC).