robcat2075

What sort of a chest is this? A pirate chest?

So if the slider moves up the lights move up? How about.... you make a image series of the lights progressing from none on to all on and use a pose to link the "frame" property of that image sequence to the position of the slider.

Are they moving in response to a slider on the console or in response to "sound"?

At AnimationMentor the next assignment would be a ball bouncing off various walls and obstacles. The challenge is to correctly handle bounces and rolls off surfaces that are not horizontal. Also the ball had to jump off the initial surface on its own.

Your squetchy bounce looks great! Here are some notes: squashNotes_200.mov

I don't really have a great eye for this yet, so I'm still getting used to it. Initially, it felt like the ball hung in the air a little long, but the more I look at ball bounces, the more correct it appears. Getting an eye for it is most of the battle. The hang time around the top is something you can play with a bit in animation. My non-pointy approximate parabolas tend to make it a bit longer than normal. Film history story...Silent films started out being shot at fairly low frame rates in the 12-16 fps range. Theater owners found they could get in more shows by speeding up the projector a bit. Film makers tried to counter this by shooting their films at higher frame rates and theater owners countered back by speeding up the projector more. All thru the 10's and 20's there was this frame rate arms race going on, and audiences got accustomed to seeing most motion faster than real-life but accepting that as normal. When sound came in and standardized frame rates and everything had to be shot and projected at the same speed audiences commented that it all looked like it was moving in slow motion!

Now don't those just... feel... better? A lot better. They dont' have the rushed look that the previous takes did. Picky points: If this were for a class, I'd leave the stripe off on a non-rotating ball test, just to avoid the rigid look of it being motionless. Unless they demand a stripe on their non-rotating ball. The moving ball looks fine and slows down appropriately. Maybe it would benefit from an even more gradual slow out at the end. You have a single continuous curve to slow the ball's horizontal motion. Straight line segments between the impact points might be more accurate (the ground can't slow the ball down while it's in the air) but not significant at this time scale. On moving ball tests I've found it effective to start on the upswing, maybe about 1/3 from the top, as if it had been tossed up. It gives the viewer a bit of time to catch up with the ball once it starts moving. It's curve of course would be a mirror of the curve from the peak. Try a squetchy ball next. My basic theory of squetchy balls is to treat the squetch as overlapping motion. A stripe on a squetchy ball is a problem that is difficult to treat well.

Here's an interesting visualization. I've taken the dropped ball and moved it sideways which is much like plotting vertical motion versus time, which is what our channels in A:M do. Theoretically these are near-exact parabolas being traced out. They are a bit sharper at the top and flatter on the sides than I tend to come up with just by eyeballing the shape. BallDropTime.mov I did this with "Time Echo" in After Effects.

Very Charming!

For the moment leave out the squetch and rotation and just do one ball bouncing in place and one that travels from left to right across the screen as it bounces and lets look at those.

Here's my sermon about Bouncing Ball. It's not really about being able to make great bouncing balls. The occasions for actual bouncing balls in animation scenes are pretty few. I don't think there was a single bouncing ball in all of TWO. It's hard to think of any big studio feature that has any significant bouncing ball activity. It IS about animating an object so that is appears to be plausibly under the influence of gravity. That happens all the time in character animation. Anytime a character steps, hops, lurches, falls, or just shifts his weight you have to imply there is gravity at work or you get that floaty, weightless look. It's exceedingly rare that we visibly caricature gravity. Mostly we try to get it very right, if we cheat it it still has to be plausible, not obviously wrong. We use bouncing ball for our first attempts in this gravity thing because it's easy to revise and simplifies the problem down to one mass rather than the 50 or so connected masses of a character. If you can't get it right with the simple ball, you can't get it right with more complicated models. David knows this already, that's why he's doing these bouncing ball exercises, but I say this for anyone else looking in, wondering why Bouncing Ball is such a big deal. David, here's some further explanation of my theory of using that first curve to inform your later bounces... UsingOriginalFall.mov

If you select it in the PWS do you at least get a bounding box showing where it is?

I haven't really followed mo cap closely. Is the BVH an object in the Objects folder before you put it in your Action?

I'm not sure what you want yet... do you want the object to be invisible but still leave a shadow?

Short Answer.... I think if you drag an image onto a light it will project it. Try that on a Kleig.

I've just skimmed thru the "Physics" pdf. I like some of it and some less so. He may be trying to fit too much info too fast into one lesson. I like the "Odd Rule". The "Fourth Down at Half-time" is getting a poor result we can see in the second half of his graph. I'll look at it some more.

I'm disappointed i don't get a chance to vote for that!

Your bounces are not wildly in error, but as they get to the smaller bounces the time problem becomes more visible. Here's some footage shot at 60fps. The stick I'm holding is marked off in 1 foot increments and is six feet long. DropTests2.mov Watch me drop the ball and the brick then go back and count frames: How long does it take the ball to fall from top to bottom? I count about 36 frames. How long does it take to fall the first foot? About 15 frames. Frame thru it yourself to convince yourself that is the case. I had to. I was surprised it took so long to get started. Almost half the time is taken up getting thru the first foot. The ball also happens to bounce up one foot. How long does it take to fall back down from the peak of that bounce? That is 1/6th the distance that it fell originally but it doesn't fall in 1/6th the time, it takes a lot longer. One sixth the time would be about 6 frames, but the ball falls that foot in about 15 frames, the same as it took to fall one foot originally, starting from the top. Presuming we have animated the first fall correctly, we can use the expectations it has created to time subsequent bounces. If the ball bounces back up to one foot, it takes as long to fall back down as the ball took to fall one foot originally. If the ball bounces back up to four feet it takes as long to fall back down as the ball took to fall four feet originally. And how long does it take the ball to bounce up to the peak of each bounce?... As long as it takes to fall back down from that peak. They are almost always symmetrical. Count the ball bouncing up from the ground, peaking and falling down again. The up and down might be different by a frame because the camera isn't quite catching it at exact moments of impact. What about the brick? I did that just to show it falls almost the same as the ball. Even though it is much heavier, it might be one frame faster. Maybe air resistance slowed the ball down a tiny bit or maybe the camera is just catching them a hair differently. Should the bounces still make parabolas in the Y channel? Yes, but they are not scaled copies of the first parabola, they are copies of the first parabola with the bottom clipped off.

There's the problem. A ball that falls from half as high does not take half as long to reach the ground. It takes a bit longer. A ball falling from 6 feet takes longer to fall thru the first 3 feet than the second 3 feet, right? Because it was accelerating all the way thru. Consider a ball that falls from 6 feet, bounces up and falls again from 3 feet. The new fall from 3 feet should take as long as the first fall from 6 to 3 feet. Consider that a fall always starts falling from a velocity of zero, no matter how high or not high it has bounced.

This is a trick question. If I'm understanding the question, it would be the same rate. That rate is on the chart from animationphysics.com that I linked to in the notes. Yes, it will always take the same time to fall x feet, no matter what height it starts at. Now... how can we use that to inform how long each bounce takes?

This is a trick question.

I'm looking at them and see a frequent problem. I'm trying to figure out how to explain it. Try this... How long does it take a ball to fall... x feet? There's probably an exact formula for that which we dont' need to calculate right now, but... How does that time to fall x feet change if the ball is dropped from x feet or 5x feet or 5000x feet? (In each case I'm referring to the time it takes the ball to drop the first x feet.) What is your expectation of what happens in those three situations?

The head looks more dog-like and the body looks more-cow like... but i like it. You could probably run the two hooks on the side through the patch as regular splines

I'm still traveling, but i willcertainly take a look when I get back home.

do that