Game Development Reference
In-Depth Information
Mirroring Animations
Normally, if you wanted your character to be able to step left as well as right, you would
have to create two separate animations, both of which would be stored in memory. Such
doubling-up on so much of the animation data can soon reach the limits of your resources.
One way to remove the need for mirrored versions is to see if the programmers on your
team can do the mirroring in the game engine. (By this I mean mirroring only the joints'
rotation and translation values; mirroring the whole skeleton would also flip the character
mesh.)
Having this aspect of animation handled in the game engine can cut almost in half the
amount of data being stored, leaving you room for more animations.
Dividing Animations
Another waytoreduce thememory consumed byanimations, without losing anyofthean-
imation, is to divide them up. Say your character is running, which is one animation. Then
she needs to hold a variety of weapons, say five. In all, you have six separate running an-
imations.
What you can do is divide them into upper- and lower-body movements. The hips and legs
from the primary run animation could also be used with the upper body animation from
each of the six variations.
Storing upper and lower body data will itself save a lot of memory. If you can, you could
even divide the animations further, into individual limbs—but this can lead to a reduction
in the quality of the animation.
As always, talk these options over with your manager; implementing this technique into
the game engine can be a big job.
Skeleton and Animation Sharing
For games in which you have many characters that potentially will do the same things, you
can create one set of generic animations that can be applied to all. In this case, it's wise to
usethesameskeletonstructureinordertomaintainthecorrectmotion,butslightvariations
in size and proportions can also work.
This sharing technique is particularly useful on more generic, nonplayer character anima-
tions—civilians, for example—where the repeated use of the same animation is not obvi-
ous.
