View Full Version : Math wizzes and 3d folks help with Expressions in Maya
deceiver
Apr 4th, 2008, 12:02 AM
So, we learned about Expressions in Maya yesterday in Animation class and it basically boils down to mathematic formulas/functions to make the walk cycle we need to do. We need to animate the legs and arms in the Z axis and the body on the Y axis.
For getting the legs to move forwards with the body, it was a simple average to do:
Body.TranslateZ = (left_foot.translateZ + right_foot.translateZ)/2
However for getting the arms to move in function of the feet, I'm not too sure what formula to be using since the left arm has to be on the opposite side of the right foot in front and vice versa. I thought I could use a Left_foot.TranslateZ = -(right_arm.TranslateZ) though that only gave the result of as the foot got further the arm got farther behind heh.
Also, for the body going up on the Y axis in function of the feet, I know it should be a sinus function, but I'm not too sure how I should put it.
Maybe... Body.TranslateY = sin(left_foot.translateZ + right_foot.translateZ), but not sure.
Help would be greatly appreciated! And for the 3D folk...well GL and Ska that I know of...not sure of the others =P. If you have expressions formulas to share for a walk cycle or other stuff, would be greatly appreciated =D!
PrivateParts
Apr 4th, 2008, 12:33 AM
Too bad this isnt COBOL, otherwise i could tell you how to do it.
offtopic:
Has ska tried ray tracing for 3d renderings?
deceiver
Apr 4th, 2008, 12:39 AM
Too bad this isnt COBOL, otherwise i could tell you how to do it.
offtopic:
Has ska tried ray tracing for 3d renderings?
offtopic:
raytracing makes almost everything look sexy.
Ginger Lord
Apr 4th, 2008, 09:44 AM
I do it by hand, if you use a formula it looks robotic. Walk and Run cycles are the hardest things to do so if you can crack them by hand it makes it easier. XSI has a thing where you do a set amount of steps and then the program works it out and you can cycle it endlessly but its a pain to get right.
I basically just start of with moving the hips/body,then one foot (sliding), then the hips, then the other foot and repeat for a few times. Then I work on the foot rolls and the lifting of the foot, once you get the lower half looking good I then work on hip bobbing and arm swinging with some neck bobbing for extra effect.
tldr: Scripts just give plenty of scope for error and you'll spend more time fixing them than you would if you did it by hand, every character/rig/environment would need a new one anyway. Do it by hand and take the hours for that into account. Or do what I'm doing in my final animation, have everyone move around on conveyor belts and for the few shots of walk/run cycles use the same scene with different environments and camera angles.
Ska Wars
Apr 4th, 2008, 11:46 AM
offtopic:
Has ska tried ray tracing for 3d renderings?
Indeed. Great for getting tha cartoony feel.
As far as scripts go, I'm with Ginger. Can't honestly see the point of them for pure animation. I can see a use if you're doing special FX (e.g. dust particles, debris control etc), but to use it to animate a character just seems mad to me. If it's one character there's no real reason not to just animate it, if it's an army of characters you'd be best off using a 3rd party program like Massive for soemthing. I really don't get why school insist of teaching MEL script during basic animation classes.
@ Deceiver. Nothing off the top of my head mate but I'll have a dig around in my books for you. If you catch me online give us a shout as I have some PDFs that might be useful to you.
deceiver
Apr 4th, 2008, 12:04 PM
I know, I'm with you on that guys. I absolutely hate doing expressions. I'd much rather do it by hand, but our teacher wants us to do it with expressions with/or driven keys, which I find pretty lame. Oh and detail I forgot to add. This walk cycle is being done with IK handles.
Ginger Lord
Apr 4th, 2008, 12:21 PM
Tell your teacher he is an idiot. Theres so much potential for it to not work, or look bad that the time spent fixing and creating such a script to save time...is wasted.
deceiver
Apr 5th, 2008, 11:11 PM
offtopic:
Has ska tried ray tracing for 3d renderings?
Indeed. Great for getting tha cartoony feel.
As far as scripts go, I'm with Ginger. Can't honestly see the point of them for pure animation. I can see a use if you're doing special FX (e.g. dust particles, debris control etc), but to use it to animate a character just seems mad to me. If it's one character there's no real reason not to just animate it, if it's an army of characters you'd be best off using a 3rd party program like Massive for soemthing. I really don't get why school insist of teaching MEL script during basic animation classes.
@ Deceiver. Nothing off the top of my head mate but I'll have a dig around in my books for you. If you catch me online give us a shout as I have some PDFs that might be useful to you.
Any luck with the books Ska?
Ginger Lord
Apr 6th, 2008, 01:38 PM
I have a good book thats Maya based but I easily transferred the skills to XSI.
Stop staring: facial modelling and animation done right by Jason Osipa
http://www.amazon.com/Stop-Staring-Faci ... 0782141293 (http://www.amazon.com/Stop-Staring-Facial-Modeling-Animation/dp/0782141293)
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