Here's another go at the flour bag. Before continuing I'll issue a bit of a warning: in an effort to conserve my precious animation paper as I tackle the basics, I'm drawing on top of some old drawings-- and not completely in sequence either, even though that would have made much more sense. I just pulled sheets off the top of the stack as I drew starting poses, ending poses, then put in all the in-betweens. So, you'll have to ignore the stuttering chaos of my previous jumping flour sack and just focus on the blue pencil. But I think my compulsive nature is ramping itself up to remedy this oversight. If you wait long enough the video might be changed and the text heretofore will be erased too, and all will be aesthetically pleasant with multiple flour sacks jumping about. But for now, back to the business at hand.
This round with the flour sack I considered the spacing of the drawings a bit more in order to stagger the timing. In the previous attempt my spacing turned out to be fairly even, which translated to a constant speed throughout the entire motion of initiating the jump, rising to the apex of the arc, and falling down to the ground without any of the dynamic acceleration and deceleration that happens in real life. But this time around, the apex of the arcs in the jumps are the slowest and the motion up and down are fastest, which follows laws of physics. To see this just toss a ball up in the air. Immediately upon leaving your hand the ball is moving quickly but decelerating as gravity relentlessly counters the initial force from your hand tossing the ball. As the ball reaches as high as the momentum will carry it with the given force initially applied, it slows, stops for an instant and changes direction as gravity becomes the pulling force and the ball accelerates back down to the ground.
Not that this animation is perfect or exemplifies the dynamics of our physical world, but it's at least better than the first attempt. AND I actually played this one at 24 frames/second instead of 12, which is industry standard. A little bit of planning goes a long way. The squash and stretch is pretty good, too. The stretch is rather subtle, though. Next time I'll do some experiments with super-squash and super-stretch to get a sense of what's "acceptable" to me. Finally, the rhythm of the jumping is really good. It's even throughout the whole sequence as the bag jumps further away from us. Another project could be to animate to music, trying to keep the beat.
Enjoy! (And remember to ignore the stuttering graphite flour sack to focus on the blue pencil sack hopping between platforms, otherwise you might have a seizure, in which case I can't be held responsible.)
ps: I await the day when these little animations are actually embarrassing and I half consider deleting this digital paper trail that details my development. That would only mean I'm much, much better. I suppose it already is quite humbling just searching around the internet and watching all sorts of animation from students to professionals then turning back here to see how much work is ahead of me. But, whatever. It's fun. Tedious but fun.