Head Over Heels: Upper Body Movement In Gameplay

Original Author: Simon-Unger

For every gameplay feature that makes it in, ten were cut so that it could survive. In the epic battle (or collaboration, depending on your team/company) between Designers, Programmers, and Animators to see these features get shipped, some core fundamentals often fall by the wayside. In games animation, it is very common to approach quality of movement in the wrong order; starting from the ground up.



In reality, the human body pivots around its centre of mass, the mid to lower torso. Through a series of complex mechanisms, humans have evolved the ability to maintain stability in three major areas of the body; the torso (the vestibulospinal reflex), the eyes (the vestibulo-occular reflex), and the head (the vestibulocollic reflex). The fundamental purpose of these mechanisms is to maintain equilibrium as well as visual focus on predators and prey. It’s difficult to run away from a sabre-tooth tiger or catch a shark with your bare hands if your vision is blurry and you keep falling over.




Her head hardly moves for the entire race! (Side note: this is also fantastic squash and stretch reference, but that’s another article)





As a former Animation Director was fond of telling us, the only animation principle you need to remember is “Force”. You cannot move an object in any direction without force in the opposite direction. The amount of force being applied is how weight is demonstrated. To make a sharp, 90-degree right-hand turn at a running speed, the character needs to decelerate and redirect his mass by applying force towards the front and left sides of his body. We can see this in action when we break down one of the turns in the video.




Taking this reference and knowledge, let’s review some in-game footage from a few random clips I found online.



Hopefully the issues in the head movement on screen are apparent to you now. These types of issues aren’t exclusive to games either. Often in feature films, especially ones with a mix of live action and CG, the CG character “feel” wrong to the viewer but they just can’t pinpoint the reason why. There’s a good chance that the character is exhibiting some of the issues described above.




So, the next time you sit down to create a movement system, try to keep the above in mind. As we move towards more elaborate motion requirements on the next gen consoles, stepping back and taking stock of the fundamentals will be even more important.

Start with your higher-frequency animations. If you have some kind of metrics system built into your game, data-mining for which animations get played and seen the most should give you an excellent starting point. Usually this means your main character’s core locomotion. Starts, stops, and turns. Try to avoid getting caught in the common trap of spending a lot of time worrying about an area that will be seen less than 20% of the time. Focus on the 80%.

