Because it is excruciatingly unflexible. A single IPO can only be used for a single circumstance, or situations that are unusually like it. Walk cycles are simply out; if a character makes a sharp turn, whatever foot he is supported on simply spin with his center of mass! I need characters to put a foot somewhere, and as long as weight is on that foot, it stays there. It doesn’t matter if the other foot is moving forward, making a turn, kicking a ball or the character kneels down; the foot that carries the weight stays put. Think about nearly all first-person-shooters: If a character is running or kneeling, and the player turns the character, it looks as if the entire character is sitting on a turning table! This is useless to me in my current work. Feet have to be able to be put somewhere, and the legs and body move around whatever foot carries the weight.
I have considered using an IPO to simulate the bent knee, and simply have it turn along with the leg. The problem is, I have not figured out how to make sure that the thigh and shin bend so that the ankle and foot line up completely.
It has to be better than the games where characters are basically running in air while simply moving along the ground. It has to be better because it is for a machinima project, and if characters are not running on the ground, the point is basically lost. Sure I can do a walk cycle or leg IPO, but the character will simply be swinging his legs without any relation to where he is. Just look at when characters in games run into a wall and keep running, their legs keep ‘running’ as if the character is still going straight ahead! And when characters turn, the legs still move as if running in a straight line.
Add to that the needed flexibility for a character to hunch, crouch, kneel, sidestep etc., and IPOs as I know them are suddenly not so well equipped to handle the deal…
I sincerely hope someone proves me wrong. I am not trying to show off any creative abilities, I just want characters that do not look ridiculous when they run, walk, kneel, etc.
EDIT: Oh yeah, and I am having a hard time testing methods with bones. After all, I cannot see the bones when the GE is running the game :-/
I am getting pretty good at animation python, but have yet to cut my teeth at GE python. I have been trying to exhaust all standard options first. I may have exhausted those now, and will see how much I can understand of this. Thanks! (if you already know some Good Stuff, don’t hesitate to let me know, please!)