View Full Version : need help with maya expressions

12 December 2002, 09:02 AM
I try to animate a futurist helmet like Matt LeBlanc's one in Lost In Space.
So I modeled all the parts that will rotate on their axis (situated on the ears of the character).
I could animated by keyframes the unfoldment of the helmet, but I'd like to create an expression that does the job automaticaly.
For example at time 0 one part of the helmet is at its initial rotation angle, then at time 10 it begins to rotate, and finally at time 20 it reaches its maximum rotation angle.
My problem with expressions is that I can't create a progressive rotation movement, I don't know how to do it.

Thank you for your help, and please excuse my english ;P

12 December 2002, 01:13 AM
I've studied a bit the expression for animation managment. I just can say that you need Maths knowledges. In you case work on trigonometric fucntion (cos, sin, tan, cos-1, sin-1,...). Note the randoms functions are very useful to add realism to the animation!!


12 December 2002, 09:20 PM
Yes I'm aware I need to learn maths to use expressions, it will be very uselful to me.
I think the function I was looking for is the smoothstep (or linstep function too). But I don't understand very well how it works.
So I found a solution : SetDriven Keys :D

12 December 2002, 05:28 PM
So look at those links and reply me!

I've another one I don't remember today, sorry!

12 December 2002, 05:43 PM
I'm working on this like, so I've a lot of links ;)

I've not found the last link yet.

12 December 2002, 09:29 PM
What about your work??

12 December 2002, 11:42 PM
Salut !
Apparement tu es français alors je vais etre fénéant et parler français :D
Merci pour les liens, les Lecture Notes sont très intéressantes.
En fait j'ai réussi a créer une expression pour mon casque. J'ai simplement associé la rotation des différentes parties du casque à la rotation d'un locator que je n'avais plus qu'à animer.

Merci encore A+

12 December 2002, 01:08 AM
Instead of using complicated expressions, I'd use Set Driven Key.

That way you could create a 'Helmet Conrtol' object and add an attribute to it called 'Helmet Unfold'.

When Helmet Unfold is set to 0 the helmet is completely folded up, and when Helmet Unfold is set to 10 it's completely unfolded.

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