Monday, August 17, 2009

Overlapping Action / Sobreposição de ações

This is one of the animation principles: it means breaking the movements, so that the character has a more natural feel and doesn't look rigid. If we are walking and interrupt the movement, the body, hair and clothes don't all freeze simultaneously at that moment. First the body stops, but hair and clothes still move. In the same way, when we start a movement, all the parts of the of the character/object don't start moving immediatelly. Ok, this is called inertia :-)

To practise, we animated a pendulum with some joints driven by a small platform. Since the upper part will move first, the second will follow, then the third and so on, it is possible to make the animation through the displacement of the movements. The graph below illustrates this. Of course, you can't only live out of graphics in animations, because there are some pretty complex movements that can be created more easily and successfully when one moves the character directly. Besides, the idea is to give life and personality to a character and this can't be done only using graphics. Anyway, it is good being able to use the graph editor!


There is an "overlap family": Follow through, Successive Breaking of joints, Drag, Lead and Follow. When a grasshopper jumps and then stops, the antennae will still move a little bit – they'll follow through. If his antennae had several segments, the first one would stop first, then the second and so on, which is called successive breaking of joints. When the grasshopper gives a big leap forward, the antennae will resist a bit, being dragged behind. At last, when the segmented antennae grasshopper jumps, his body will lead them and they will follow, one segment at a time. Maybe this grasshopper abstraction isn't the best, but it's what came to my mind and it is cute in a way ;-)



Este é mais um dos princípios da animação: significa quebrar os movimentos, de modo que o personagem tenha um jeito mais natural de ser e nao pareca rígido. Se estamos andando e interrompemos o movimento, nao há um "congelamento" de corpo, cabelo e roupa no momento em que se parou. Primeiro o corpo pára, mas o cabelo e as roupas ainda se movem. Da mesma forma, quando iniciamos um movimento, todas as partes do personagem/objeto não comecam a se mover imediatamente. Ok, isso se chama inércia. :-)

Para praticar, animamos um pêndulo com algumas juntas. Como a parte superior vai se mover primeiro, a junta logo abaixo se moverá depois, então a terceira e assim por diante, é possível realizar a animação criando um deslocamento entre os movimentos. Para ilustrar isso, coloquei o gráfico abaixo. É claro que na animacao é difícil se viver apenas de gráficos, pois há movimentos muito complexos que se pode realizar mais facilmente mexendo no personagem diretamente. Além disso, a idéia é dar vida e personalidade ao personagem, e só com gráficos isso não é possível. Mesmo assim, é bom poder usar essa ferramenta!

Bem, para terminar, vale mencionar os termos mais usados comumente quando se fala deste princípio: Follow through, Successive Breaking of joints, Drag, Lead and follow. Está tudo interconectado.
Follow through: quando, por exemplo, um grilo pula e depois pára, suas antenas ainda vão se mover um bocadinho na direção do pulo.
Successive breaking of joints: se a antena dele tivesse três segmentos, o primeiro pararia antes do segundo e o segundo antes do terceiro.
Drag: quando o grilo der um grande salto para a frente, suas antenas irão resistir um pouco, sendo arrastadas logo atrás de sua cabecinha.
Lead and follow: por fim, quando o grilo com antenas segmentadas saltar, seu corpo irá "guiar" as antenas e elas irão seguí-lo, um segmento por vez.
Hm, talvez a abstração do grilo com antenas não seja a melhor, mas foi o que me ocorreu agora e até que achei meio engraçadinho ;-)
De qualquer maneira, aí está a animação aplicando esse princípio!




3 comments:

  1. That is a great practice project. How did you plan this one? Did you move the 1st joint then copy the animation down the chain? Then offset the keys? Just wondering

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  2. Hey David! Yeah, that's how I did it :-) But in some moments, I had to take a different approach:
    - when the platform moves for a longer time, all curves meet. That's because eventually, the platform should reach a constant speed (well, I'm assuming that ;-) ) and the joints will reach a limit rotation for that speed, so I don't want them displaced anymore.
    - When it hits the ball, there is also some deceleration - frame 116, marked with the red line. So in that moment, the curves becomes less steep.

    How did you work on yours? I saw the platform really moves a lot. Did you use the graph editor most of the time too? I thought it was really nice being able to use it like that :-)

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  3. Hey Sunshine!, I think it's awesome the fact you explain all the concepts that we have learning every week at AM, I wish I could do that on my blog, actually a lot of friends of mine have asked me about this cencepts we've learned, but it's so hard to put all this information together in order to someone really understand. So... I'm gonna write a line about it on my blog , and I'll send all my frinds from Brazil to here (hehe) so they will be able to get all this precious information!

    Im was wondering how did you learn portuguese?, it was just for the interesting? or do you have any relatives here in Brazil?

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