The Perfect Walk Cycle! - can it be done?! Or there are things you cant avoid..

[timothyc]

Hi

First off, since this is a robot you have a lot of lattitude for interpretation (who's to say how your robot is supposed to walk?)

But to critique it from a more realistic human perspective (but my apologies I couldn't get this damn computer to step frame tthrough your .mov):

1. The feet should strike the ground heel first, and then the sole should slap down pretty fast. It looked to me like you left the keyframes to interpolate from foot-positioned-an-inch-or-two-above-ground to foot-flat-on-ground. You need to keyframe the heel-touch and then 2 or 3 frame later (depending on walk speed) rotate the foot from the heel edge to place it flat on the ground very quickly.

2. On the foot-on-ground phase, You've bent the toes to raise heel too soon. The longer you leave the heel down, the more "power" the person is putting into the stride (like walking up hill). You can add to this effect by straightening the knee just before the foot is raised, giving the effect of a "push off" against the ground.

3. you've left the pelvis unanimated so that it maintains a fixed orientation throughout. How about some roll and yaw movements?

4. About the knee pops. I don't get to use Maya very often, but I think there's a display mode that shows you trajectories (not as good as Max's, unfortunately). If you can show the trajectory for the knee, with tick marks for inbetween positions, you can use IK to move the foot while simultaneously monitoring the amount of knee pop. I find this immensely helpful. When things get really tricky, sometimes I've been forced to convert to FK and fine tune any popping.

5. In general, from the side the body seems to have it's centerof mass a bit too forward. Not a mistake exactly, just a bit out of keeping with a loose, relaxed Jar-Jar Binks style walk (Oops, did I say the JJB word?)

TC

[WesleyChandler]

Thanks timothyc, I'll definatly keep that in mind when I go at this again. To your answer on #2. I find that the longer I keep the foot flat on the ground and then applying the "pushfoot" at past mid-stride, it makes the knee slow down or even stop at that one spot in space. Is that natural? Or as soon as I create the push foot, I should speed up the translate Z in order to counter act it (translate z = his direction of travel)?

[timothyc]

I can't say I've ever noticed that effect in my own work. It might be one of those things that looks wrong only because you're excessively focussed on it.

Re: something I said earlier. IIRC the Maya trajectory display was called motion trails. Annoyingly, the display waits for you to release the mouse before it updates so it won't give you realtime, interactive feedback of your knee pops. It's still useable, but not as good as it could be. (Maybe the latest version of Maya fixes that.)

Also, about your problem smoothing out the kneepops while keeping the feet locked: I think you overlooked the fact that in a 2-bone IK chain like the leg, any knee popping is controlled by not only the ankle end of the chain (which I guess is what you were doing), but also the hip. e.g. to pull the knee in you can either move the foot further away or raise the hip slightly. And that relates to my comment that you should add some rolling hip movement - if you put in some pelvis rotation you can fix the knee pops at the same time.

TC

[el_diablo]

I have about the same observations as timothy, I would just like to add it seems to me your hip is way to high, You are overextending the leg.

http://www.idleworm.com/how/pic/a0002/wlk08.gif

Look at the pelvis positions in that gif.

[WesleyChandler]

Thanks Timothyc and el_diablo. I'll have my shot again at this soon and I'll definatly keep your tips in mind!

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