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random wiggle bone rotation?


thefreshestever

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hey guys,

haven´t been here for a while, and of course i have a question:

 

i´m trying to find a way to simulate a stop-motion look without having to animate frame by frame.

 

so i thought a possible solution would be to add some sort of random expression to the bones rotation, so that they would rotate randomly with very low values (let´s say from 0,1° to 0,3° or so) each frame.

 

i´m not very familiar with expressions in a:m, in after effects the wiggle expression is fairly simple and can be applied to almost every parameter. i hope it´s similar in a:m.

 

any advice?

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I posted a flour sack test that looks sorta stop-motion here...it's just having the interpolation set to "hold" for everything.

 

As for an Expression...something like this might be a decent starting point:

 

If((GetTime()*Rand())

 

It would need tweaking because GetTime() would be an ever-increasing number...which would cause the jitter to start small and increase until it hit the limit (it also would only jitter to the positive rotation of the bone.

 

This would need more thinking.

 

Hope that helps.

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thanks david :)

 

unfortunately this script overwrites the animated position of the bone, so that´s another issue... and i´m no good in scripting at all. :huh:

 

setting the keyframes to hold would give a rougher look as i am looking for. i want to animate at 12fps without having to animate each frame and still get some sort of slight jittering.

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Here's something you could try...it's more complicated than I think it needs to be, but some other things I tried gave me some errors I haven't figured out yet

 

Hope that helps.

 

 

 

 

unfortunately this script overwrites the animated position of the bone, so that´s another issue... and i´m no good in scripting at all. :huh:

 

If you put the jitter on a bone that is the parent of the one you are animating, you can still move the bone...that's the way I'd do it.

random_jitter_test_11_03_2012.prj

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you´re a genius!

it does exactly what it should do, but you´re right, seems a bit complicated, especially to set up a whole character like this to make every or at least most of the joints jitter.

 

i have a tiny bit experience with action script in flash, there i would try something like to get the current position of the bone and add/subtract a random value within a defined range. in flash the script would calculate the position for each frame. does that make sense to you?

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seems a bit complicated, especially to set up a whole character like this to make every or at least most of the joints jitter.

 

i have a tiny bit experience with action script in flash, there i would try something like to get the current position of the bone and add/subtract a random value within a defined range. in flash the script would calculate the position for each frame. does that make sense to you?

 

How about like this? It has a bone set to jittering all the time with each bone having an "orient like" constraint to that bone (with "apply before action" on) in a separate Pose. Then, you animate your character like you want, go back to the beginning of the animation and turn on the Pose to have the bones "orient like" the jitter bone. Here's a simple example (I didn't include the negative bone since it was a quick test).

 

Hope that helps, Sebastian.

random_jitter_test_11_03_2012b.prj

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Here's an additional idea... instead of manually changing the multiplier in each expression, you could initially set some number larger than you would ever want and then later reduce the over all effect by lowering the "Blend Ratio" under "blend method".

 

That number could also be set to zero during holds so there is no jitter at all, as with a tru stop-mo model.

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