Quick Trick: Less is More

This is just a short one... short but good.

With physical animation, always remember that the body ( be it human or otherwise ) is a machine, run by a brain, that is obsessed with efficiency.

The human body likes to use the least amount of energy possible to do anything. Thats why we almost fall over every time we take a step, because evolution has enabled our brains to understand gravity, and use it to our advantage in everything we do.

A good way to show this in animation, is to try and take the least amount of steps possible if we need our character to do anything. If they need to turn around, or stand up, or walk over and pick up a bunch of flowers, or do a run up before jumping out of a window... use only as many foot plants as you absolutley need. Your poses will look better too with nice wide and clear contacts, and your actions will be stronger.

If you're having trouble technically with the footplants ( e.g, the distance is just too large, or the foot needs to reach an akward pose ) try these ideas to help:

• Can you shorten the overall distances if need be ?
• Try sliding the feet a little ( this can really add to the organic feel sometimes )
  
• Try a very small hop ( just a small bit of airtime on both feet )
  
• Change the timing on your main action to allow the foot to plant without stretching
• Remember to pivot off the tips of the toes when fully extending
  
• Twist, swivel and roll the feet. They are extremely versatile
• The audience probably isnt looking directly at the feet... cheat

Just bear in mind that occasionally you may want to deliberatley animate a characters feet in an unrealistic way for certain effect ( imagine the classic fast "tiptoe" sneak from the old Tom and Jerry cartoons )... but as a general approach, you`ll find this idea can really help with physical actions, particularly in their clarity.

Quick Trick: Feet First

I'm gonna hit up a few posts I've had in my mind for a little while, and as a temporary "theme" I thought I'd concentrate a little more on physical animation ( seeing as that's actually what I do most of the time ) and some of the tips associated with that type of movement.

So... "Feet First" ... ok...

What this post is about is a quick way to ground an animation with a sense of weight and force, and then worry about all the other parts after that. I'm trying to explain the idea of "contact points"... the point(s) of the character's physical structure that are generating momentum and push. I like to concentrate on this early on in animation, and it never lets me down.

For a start its always good that when you come to "animate" your scene ( as opposed to the blocking stage ) to start with something first and get it feeling solid. Animation is just way too hard anyway, without trying to think and animate everything at once. As an example, many animators will start by working detail and smoothness into the characters main movement point ( usually the "root", e.g the hips or the waist of the character ) because it makes sense to do that as the root is often first to drive a full body movement... and the rest of the body will generally inherit movement from this. This is a pretty basic animation concept, and a good one to use.



Work "from the top down"

But where is the "top" really ?

What really leads the movement? ok.. so really its the thought, the motivation, all the cerebral stuff, and this could go pretty subjective because it can depend a lot on the scene and what the character is doing, but I find that for physical animation, a lot of the time its the points of contact that lead the action! So most of the time its the feet, or maybe the hands ( if your character was doing push ups for example ) or the elbow if your guy is leaning on a bar.

If you think about it, the root of the character cannot actually move itself. when you twist your hips, you're using mostly your legs to do this. When you shift your weight, your hips might appear to move first and drive the movement, but really that movement is being generated by the legs and feet!
The root can only move itself if the legs stop pushing, there are no other points of contact ( e.g no bar to grab onto ) and gravity brings the root downwards.

If they're not leading a direct movement, they at least drive the overall weight and grounding of a character that is very important to get right in physical stuff.





As a working example, I recently animated a pretty complex action, where a guy is lunging forward a few metres and supposed to be not very firm on his feet and a little lacking in confidence. I wanted to get the feet shifting nicely and that idea of him "catching himself" almost as if he was just about to fall over.
So I blocked all my main poses first ( I actually used each new foot plant as a key, then I set a breakdown between each plant ) ... then I jumped straight in and started to animate the feet and the root, and took them both pretty near final. Once I had that working, with a nice sense of timing and weight and force, I could have fun with the rest of the body. Its not just because the feet movements were important to this animation, I would also do this if there were only a few plants or a simple weight shift.
For most physical stuff you will find that if you animate the feet and the root together, get the timing and weight feeling right, then its much easier to animate the rest of the character, because the main driving forces are established and already working.

So...

Working between changes in contact points sets up good "markers" that you can work around. You know that's where key forces are either constant, moving to, or moving from.. and a lot of the nice overlap and subtle stuff that you like to animate are direct results of these changes... so start there.

Quick Trick: Push Off !

Well, seeing as this is an animation blog - its about time I posted something up that actually moves. Well here goes. The video link below is a walk I did recently, mosty as a test for a new rig my super talented colleague Goosh is currently working on, but also something that I can use as a good medium to discuss a certain aspect of walk cycles that commonly gets overlooked.


This was really fun to animate. It`s not "true" quadruped locomotion, as it was difficult to accomodate the large stretch of the back legs with the front legs that are shorter and still retain a nice feeling of timing and contact.

First off - this isn`t by a long shot the worlds greatest walk cycle - in fact its pretty run of the mill, but something that I see time and time again in 3D walk cycles is the lack of a good "push off" in the feet, and believe it or not I see it over and over in most CG features.
What I mean is this - as the foot travels backwards in contact with the floor, and begins to get ready to lift up and travel back towards the front, there is a subtle but very important rotation that travels from the ball of the foot and through to the toes. The mechanism for this movement, and the logic behind it, is that the foot tries to retain contact with the ground as long as possible, essentially rolling the foot as far onto the toes as it can go without looking stupid. The body uses more energy to lift the leg through the passing position that it does keeping it planted on the floor.
Many animators overlook this push off, and start to bring the foot back towards the front with hardly any rotation from the toes. It still works, but the feeling of weight and locomotion gets diminished.
We often hear as animators how important it is to show "contacts". This is so true, and good contact poses will be integral to selling a feeling of weight and interactivity with the world. But "push offs" are also contacts - they just happen as the contact is getting broken rather than created.


I've isolated the back legs in this video to clarify this idea ( ignore the repeat frame ). You can see as the foot travels back, there is a pretty large rotation, that travels through the foot, and the toes are still contacted for alost a full 7 frames after the other foot has made its opposite contact plant. OK, this is a pretty stylized ( cartoony ) walk, but the concept still holds very true in more realistic animation.

As a general rule through all my animstion, cycles or not, I try to keep weight bearing contacts planted for as long as possible without looking stupid. It's also generally good to use as least amount of footplant possible to carry out an action, unless the creature's character would dictate otherwise.