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View Full Version : Jerky Knee Problems - Walk Cycle


mattjmit
05-07-2008, 06:27 PM
I've got an annoying double jerk thing happening at the back of each stride in this walk cycle...

http://www.youtube.com/watch?v=2FHVijWNaR4

Everything below the knee seems smooth, what can I do to make it better?

Thanks.

Capel
05-07-2008, 07:58 PM
well first off you're gonna want to nail down the movement of the body and the hips before fixing the knees. otherwise you'll fix them and then tweak the body and it'll most likely make the knees start popping again.

once you final the body and hips you may have to go in and smooth out the knees on 1's. it really depends on the rig.

mattjmit
05-07-2008, 08:33 PM
Hey thanks for your reply capel, realy dig ur quote too!

So you recon I should finish off the walk as far as the arms before I go tweaking anything with the legs?

What's your process when it comes to building a generic walk?

Thats for anyone else who wants to answer too.


Thanks,
Matt.

Capel
05-07-2008, 08:42 PM
you don't necessarily have to finish the arms before finaling the legs but you can if you want. it's more about the body. in a walk, everything works off of the body. the overlap of the head, the swinging of the arms, etc. so once you've nailed that down it's safe to finish everything else. the question you should be asking yourself in any shot is "what leads what?" and build from there.

i build a walk starting with my contact poses, then adding the passing position, then the down and the up position, all in stepped. then i go in starting with the body and take the curves from stepped to spline one at a time. there are other ways to approach it, but this is mine.
i learned it from the Animator's Survival Kit. that book is really great. i'd pick it up if you haven't already.

MoutMout
05-08-2008, 12:39 AM
Hi guys!

I'm totally agree whit Capel, you have to move the hips because walking is like fall and fall again but you don't because your legs are here to stop the fall.

So your hips fall in a direction and your leg receive the weight of your body and push it away then your hips go to the oposite direction and the other leg push it away...etc

Hey capel, sure the animator's survival kit it's very good book, I've learnd a lot with it :)

mattjmit
05-08-2008, 08:37 AM
Thanks guys!! I have the animators survival kit also, its a great resource.

Capel, when you say you do the key poses 'stepped' is that when the graph is set like:

...............__________
_________


??

and splined is with the smooth transitions?


just needed to check.

I did the walk Contacts/Down/Pass/Up but sometimes the feet are out on the pass position so maybe I'll do it Cont/Pass/Down/Up and see if it makes any difference at all. It makes sense to break it down in halfs, thats how I would do it drawn.

I'll put the finished walk up for crit or before I finish if I run into probs.

Thanks again for all your help and time.
Matt.

mattjmit
05-09-2008, 05:28 PM
I've updated the cycle, It's not great but my main issue is still the knees, I'm going to try a few things but in the mean time, could any of you guys tell me where you think I might have gone wrong and how best to fix the jerky knee issues?


http://www.youtube.com/watch?v=2_wA08r-XPI

Thanks guys.

MoutMout
05-10-2008, 12:48 PM
For the stepped animation i think Capel would say you have to find the "key poses".

I mean the main position of your character in your animation...And for the graph you can use this solution wiich's called "block animation".

And to finish your hips' character still not move, you have to move it up and down much more. If I find the time I'll make you the main poses in a basic walkcycle.

Good luck ^^

PS : sorry for my english today i'm a little tired :P

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