Different ball weights

[Jero3D]

Update:

http://boxstr.com/files/6192433_rwuli/animate%20-%20heavy%20%26%20light%20ball4.mov

Please critique!

[Jeremydjutras]

Hello Jero3d,
I like the heavy ball, but the light bouncy ball:

After the contacts, it seems to shoot up TOO fast. You want to have descending energy through time on the ball (given that there are no external forces applied to it, or it is not alive), so to have it losing height throughout is great but you also want to slow it down as well.

Another reason why the contacts are not working so well is that the ball has no squash as it is influences by hitting the immovable ground. There should be a contact pose (a stretch leading from the last key with the other end just touching the ground), then a squash pose, then he last point of contact pose (another stretch pose leading from the squash pose into the next pose, with the bottom end still in contact with the ground).

Maybe squash it at the top of your arcs too, for added flexibility in the ball.

If your ball rig does not have these deformation abilities, you can find one here:

http://www.creativecrash.com/maya/downloads/character-rigs/c/the-bouncy-ball

happy animating!

[robcat2075]

Another problem with the bouncy ball is that it actually spent more time in the air during the second hop than it did for the first hop even though it didn't rise as high. That feels very odd.

Bouncing balls lose energy with each bounce. The less altitude they gain, the shorter the distance they have to travel, the less time they will spend doing it.

[Munjeni]

There's another problem everyone seems to be overlooking. purely from a physical point of view, two balls, dropped at the same time, fall at the same rate. Gravity is a constant, it's roughly 9.81 m/s2 , that is, 32.2 ft/s2, here on earth. The mass of the object does not have any effect.

The only reason why light objects fall a bit slower than heavy objects is the air resistance, which affects the lighter object a bit more, but is more distinct with objects with a greater surface. With two balls of the same size, the difference should be slight. Your basketball is falling roughly two times faster than the bowling ball. Even with some artistic leeway, it's quite a large difference, and it makes the animation seem weird, at least in my opinion.

[giordi]

mmmm the heavy ball is good but.... i feel some inconstant stuff...i mean... the translation of the bounce and also rotation aren't constant the are a bit fast slow fast slow...fasr and slow... that make the animation really weird.
Also u have a problem in the arc of the jump it's again incostant try to work on your hypergraph..(i'm speaking about maya if u don't use maya goi to fix the curve of animation)

[Cerilli]

Another thing that I feel might be throwing you off a little bit is that the bouncy ball is moving forward quite a bit. It seems a bit strange because it is being dropped straight down, and there does not seem to be any force that could explain its sudden forward movement.

Personally, I think it might be easier to start with getting it to bounce straight up and down perfectly first, and then adding other stuff (such as forward movement, rotation, and squash and stretch) later. Doing that might help simplify things and make the process easier for you.

[Jero3D]

Thanks everyone for the critiques!! I tried to correct most of the things that you said. I made the ball fall to the right so it looks believable that it bounces to that direction. I also made it fall kind of at the same time as the heavy ball and I reduced the timing as it bounces so it loses energy. I changed the arcs also but I didn't add squash and stretch because I wanted to try and make it without it. I will try to make another version of it with squash and stretch to see how it looks like.

Here it is:
http://boxstr.com/files/6270043_xbieb/animate%20-%20heavy%20%26%20light%20ball5.mov

Please comment!

[giordi]

i'm sorruy but doesn't look like a real bouncing yet
i can see still the same problem... the spacing is wrong and probabily after fixing the spacing u have to look a bit in timing

[Jero3D]

I can't clearly spot the mistake, but I changed the spacing a little bit and made it slow down on the second bounce.

http://boxstr.com/files/6272401_qd4np/animate%20-%20heavy%20%26%20light%20ball6.mov

[Wualforvalle]

thats why physics is soo important, and more for animation...
i love physics...

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