The do's and dont's of computer graphics

All things in real life is random, more or less. The way branches are positioned on a tree, the way soldiers noses point when lined up, the way chairs are positioned around a table. You could say that parallel things don’t exist, equally spaced things aren’t and all lights don’t shine the same amount, and there’s certainly not one painting that hangs straight.

So the advice is to put things out of order, think twice before you let something just be as it is, keep nudging things to make them convincible, or even better let your computer add a little randomness to the position or alignment of them.

Still not convinced, well get a tape measure and measure a "square" room. Be sure to measure the length, height and width in every corner. Done that? Got the same height in every corner? Not? Here I could say told you so but I don’t.

Now get rid of the tape measure and start looking around. See any thing without any dust, scratches or other imperfection? Now look at your last 3D rendering, see anything with any imperfection? I would be surprised if you did, but if we want our pictures to look real and believable, then it has to be there.

Dust is easily added with a little randomness to the texture, in case you want more control over your dust and grime, you need to add it via a map. In some cases you can add it directly on the objects main texture, but often you have to have a separate map for the grime (most often when you have a tiling map). Scratches can be added with a bump-map.

Things seldom move in an orderly fashion. You can always find things that does, but most things don’t. Look at a person swimming, every stroke looks quite the same, but not exactly the same. Animations using the same stroke over and over again will look artificial. Once again we want to have some randomness. Clocks and industrial robots on the other hand have perfectly repeated movements.

The first rule of motion is that if there is anything living involved there will be some form of randomness involved in the motion.

People standing still are in balance. People in motion are generally in balance. Although some explain walking as repeatedly bringing yourself out of balance and then getting the balance back. When walking you cant get your balance off too much, or else you will fall(which might be what you want), the same thing goes for every other animal and machine.

The second rule of motion is keep your balance or else you will fall.

A boxer getting a punch in will cause the other boxers head to roll back at least a bit. Things like that happens all the time in real life. Its called secondary motion, many animators forget this kind of motion, and only animate the primary motion. Often forgotten secondary motion include vibration, things moving due to draft, things not stopping to move after you let them go.

The third rule of motion is things interact.