Outside the Box:
By Paul "Villam" Steed
For today’s exciting walk animation tutorial I’ll be using 3DSMax R2.5 and the plugin known as Character Studio R2. However, I’ll be focusing on technique over tool features or functionality so you can apply the lesson to any package. Thusly you need to understand really complex terminology like rotation and view and axes (brrrr…tough stuff, huh?)
When doing a walk cycle you need to adopt the same rule that applies to splitting a pair in Blackjack: make one good before the other. This means make the walk look good in one axis or view then switch to make it look good in another.
Ah, here’s our lovely model Shauna, now.
Accompanying the ravishing Shauna is her wire frame counterpart and Biped ensemble. The latter of course serves as a skeleton and is what’s actually animated. Combined with Physique, biped deforms Shauna’s mesh accordingly as we animate her. Most modeling and animation packages use this sort of bones-within-the-mesh approach so it should be a familiar concept. But, as I said before this isn’t a tutorial on how to use Character Studio (next time, maybe), it’s a lesson on making a decent walk cycle. For clarity sake I’ll refrain from showing the Biped and sexy Shauna only, just wanted to show what the Biped looked like.
So going back to the Blackjack corollary we’ll start in a side view (right) and get ready to position the model for the first step in the animation.
Now we move her arms and legs into an extended stride position. For the sake of this tutorial we’ll put the right foot and left arm forward, and the left foot and right arm back.
Don’t worry too much about foot or head position/rotation at this point. Let’s just get the gross positioning in. Another thing. Keep frame 0 your default position and move to frame 1 for this first pose. Do this for two important reasons. One, do it to give you a fall back non-animated pose, and two, do it to keep your total frame count easy to follow (i.e. on frame 10 you have a total of ten frames of animation; if the first frame of animation was 0 in the walk cycle then frame 10 would denote eleven frames of animation at that point. Verstehs du mich?)
Next we set the other gross default pose at frame 8. Why 8? Glad you asked. A general rule of thumb in a walk cycle is match your total number of frames for one cycle to your playback frame rate. In other words a single walk loop is about one second long. Our playback here is at 15 frames per seconds but, although I’ve noticed most are odd-numbered when dealing with motion captured walks and runs, even-numbers work better for key framing purposes. Frame 8 is the halfway point to 14 frames. Thusly, we add 7 to 1 and advance to frame 8 (do not pass go; do not collect $200) and reverse the position. I basically grab the left arm and right foot and move them back to line up with their brethren appendages then eyeball the other two into the position.
Now if you were to play back the anim at this point you see this very mechanical motion of legs and arms exchanging their forward and back position. Since this is a looping animation, we need to get Shauna back to her starting position of right foot forward. To do this simply copy keys on frame 1 to frame 15. 15 you say? Yes, 15 because even though the animation spans 14 frames (1 – 14) copying frame 1 to frame 14 would result in a hitch as the frames loop into themselves and repeat the first and last frame. Hence copying to frame 15 leaves a smooth transition and no repeated frames.
Cool. We’ve blocked out the rough frames for our walk cycle so it’s time to get busy. In a casual walk your leg that stays in contact with the ground remains pretty straight unless you’re crouch walking for a specific reason. The other leg is basically dragged along and put forward as you essentially fall to the ground. Walking is just a sequence of catching yourself as you successively fall forward, right? Obviously. Thinking in terms of the falling and catching helps keep your mind on weighty matters. Weight distribution and balance are key to animating figures since there’s no real ground for them to step on (unless you’ve got some swanky collision-detecting IK solution going).
Credits: Thinking Outside the Box logo illustrated and is © 1999 Dan Zalkus. Thinking Outside the Box is © 1999 Paul Steed. All other content is © 1999 loonyboi productions. Unauthorized reproduction is strictly prohibited, so don't even try it. We've got really big guns, and we're ripped, baby.