Walk Cycle

[Shelton]

Here is a test. I know its large so Sorry about that. I having problem with the popping of the leg. Any help would be appreciated

 

Steve

walk.mov

[Darkwing]

Without having looked, popping I do believe occurs when you make the leg too straight. At it's straightest point, it should still have a slight bend at the knee

[robcat2075]

"knee pops" are a persistent problem in CG walks.

 

Basically...

- the knee goes forward as the leg moves forward into the next step,

-then is drawn back as the leg is pulled straighter to put the foot down,

-then is pushed forward again as the leg bends into the squash pose.

 

And when these reversals happen in a few frames it's an un natural "pop". This much is probably obvious to you already.

 

 

In this case, most of the problem is that the knee is going too far forward in the first motion because... the foot is being lifted too high when it is brought forward. The higher the foot is lifted, the farther forward the knee has to go just because of the geometry of the bones.

 

Watch my videos on posing out a basic walk and pay attention to how the lifted foot is only barely skimming the ground as it is brought forward. For almost the entire travel either the toe or heel is clearing the ground just enough to not drag.

 

We *think* we have lifted the foot high because, initially, the heel is peeled quite a bit off the ground (to get the toe off at all) and perhaps because of the work involved in moving the entire leg.

 

I think I also plotted out the forward motion of a knee in that vid. In a normal walk it never goes backwards in real space. It may move slower than the rest of the body but it's always moving forward. So it is geometrically possible to walk without popping the knee, but hard to manuever in CG.

 

Last ditch resort... If your legs are rigged to be scalable you can adjust that at moments to hide the pops. Sometimes just a few % of scaling is enough to pull the knee back to where you want it. Pixar animators do that. But do that after you have done everything else to fix the proper motion of the walk. Fix knee pops last in walks. Get all the other motion working right first.

 

Another note, not specifically knee related... he is lifting his rear foot off the ground at the same instant the front foot is landing. That's too soon unless he's almost into a jog. The rear foot and toe have the task of pushing the body forward onto the newly planted leg so they wont' leave the ground so soon. Look at my vid and count frames to see there is that span of time where both feet are on the ground.

 

Also... i think the landing foot is taking too long to settle flat on the ground. that usually gets slapped down in a frame or two or three because of the weight of the body on the leg.

 

Here is a test. I know its large so Sorry about that.

You can recompress to a smaller codec in A:M or in QT Pro.

[Shelton]

Thanks Robert

 

I will pose another walk this evening. I wanted an exaggerated walk by lifting the legs high, but i think a simplier walk is in order. I will re watch the tutorial this evening.

 

Is there a way to place markers in the action?

 

Steve

[robcat2075]

Is there a way to place markers in the action?

 

If rulers are on they should be possible like in modeling mode.

[Meowx]

"knee pops" are a persistent problem in CG walks.

Just watched your tuts on a walk cycle, not sure how I missed them before. Those are absolutely fantastic, especially after coming off Animators' Survival Kit and having your vids to apply the stuff directly to A:M. Cheers!

[robcat2075]

especially after coming off Animators' Survival Kit and having your vids to apply the stuff directly to A:M. Cheers!

 

TASK is a great resource and one could learn just about everything in the first two or three quarters of AnimationMentor from that book