Download the project files here (.sit) If you're on Windows and you don't have the stuffit engine, download the free stuffit expander for Windows here:
#1 - Our character:
The modeling of the character is an ideal beginner's project - just a bunch of cylinders and extruded shapes.
Our character is both animated by manipulating whole objects and by moving the bones skeleton (arms, legs, spline) which requires a bit more detail in the joints. Not to repeat my previous mistakes, this time I modeled the character with the arms spread out.
The simple shapes made it easy to equip the character with its skeleton. Notice that besides the anchor bone there is another small bone in the shoulder that is set to only rotate around its z-axis. This is to have the arm move inside of the shoulder-nut without moving the nut itself.
#2 - Character skeleton:
#3 - More mesh detail for the joints:
#6 - IK track keeps the leg in the foot:
This is a bit more complex, so take some time to study #5: Character's object hierarchy
Bone skeleton and geometry are treated separately from each other. The leg has three bones and an empty object 'NullFoot' at the end of the chain. The foot geometry is completely independent from the character. It contains the null-object 'TargetFoot', which serves as a target for the IK-track of 'NullFoot'.
The effect of this is as follows: You move a foot, record its position and the leg will automatically jump back to the foot. Or: You move the whole character, record its position, and the legs jump back to the foot. This prevents the infamous sliding feet and makes animating a walking movement a lot easier.
The empty object 'NullBody' moves the whole upper body: two-part spine with the head and arms. Moving the object 'NullHand' moves the arm up to the shoulder anchor (including the paddle in the right hand). The head can be moved independently but is equipped with an empty object that has an IK track targeted at the ping pong ball. This way our character always looks at the ball - one thing less to worry about.
Posing the character
After our character is completely modeled and boned it is not very hard to put him/her in all kinds of poses. Here is how I usually went about posing the character:
1. Move the whole character. Record. (legs jump back towards the feet)
2. Move object 'KörperZieher' with IK. This bends the upper body Record.
3. Move object 'AnfasserHand' with IK. The respective arm moves. Record.
4. Move object 'FussRechts/Links' (FootLeft/Right). Record. The legs will jump into the feet. (if they are able to reach them).
#7 - The character comes alive:
With this, you can bend your character into all sorts of poses. Be careful to not be too extreme - it is, for example, possible that by bending the head too far, the nose gets into the influence of the breast bone and was pulled out of face. But all in all this skeleton is very flexible and just what I needed for a ping pong match.
Animating the service
At this point of time I didn't know if it was possible for be to actually animate a ping pong game, so I started with the service, which doesn't make big movements necessary. I put the character in front of a simple table and started animating the ball. The ball should be thrown straight up in the air by the character, fall back down, get hit by the paddle, hit the table and make its way over the net. 6 keys for the ball:
Key1: Starting position on the character's hand
Key2: A bit lower (character pulls hand back for throwing)
Key3: Highest point
Key4: Ball hits paddle
Key5: Ball hits table
Key6: Ball over net
What really helps with adjusting the ball's flight curve is Cinema's space control (#8 - if that's what it's called in the English version), that lets you control the balls speed and position very efficiently. When I was happy with the ball's flight curve, I could pose the character accordingly.
The starting position is with knees slightly bent, left hand 'holding' the ball. At Key2 this hand moves down just a little bit, then moves back up quickly a few frames later, throwing the ball up. At Key3, the ball's highest point, the character moves back his right arm and stands up a bit and lifts the left foot, ready to hit the ball. Key4: The paddle is under the ball and the left foot back on the ground (a lot of ping pong players reenforce their service by stomping on the ground). Key5/6: Our character can relax.
Quicktime Movie Service (127kb)
#8 - Ball's flight curves in space control:
#9 - Ball's path for the service:
Animating the service worked out better than I had ever dreamed off and it was time for a partner. Again I started by animating the ball's flight curve back and forth for about 20 seconds. Then I posed the first character accordingly and eventually copied him a partner who had to undergo the same procedure. To have at least some kind of story, the first character loses the match but doesn't take it very well. He throws his paddle into the net (deformed by FFD), crushes the ball and walks away shaking his head. At the end he kicks one of the nuts on the ground into the camera.
I hope this tutorial has encouraged some of you who always wanted to do character animation - it's not that hard.
Some Quicktimes from the Game:
Angry character (439 kb)
Part of game I (308 kb)
Part of game II (645 kb)
Feel free to discuss this technique in the Cinema 4D forum at Creativecow.net.
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