Gnomon DVD: Spring Effects
Springs are useful in lots of applications in maya. Follow through and easing are important aspects of animation and are easily achieved with the help of springs.
The first example shows a camera that moves around with springs attached. It is set up with two single particle in a cube, add springs, and then just point constraint a locator to the particle that can parent a camera to it, and aim constraint to the other particle on the other end. This simulates a POV of a character on a horse.
The next example shows the usage of a soft body cube with springs connected to the vertices of a larger cube containing it at the edges, and the soft body has its own springs. The soft body has 2 more particles at opposite faces binded by springs to the respective vertices near them. This simulates an even more jiggly motion if a camera is parented to it. We can always connect the worldCentroid attribute of the particle to the translate of a locator to constrain them together.
Using the same setup, we could apply it to other types of geometry. Alex recreates the Star Wars Pod Racer using 3 cubes within a big cube with springs set up at the ends and 2 particles on each face of the 3 cubes for orientation (point and aim).
Another example is the crate connected to 4 dangling ropes. It’s basically similar approach of connecting particles to vertices with springs, except that we need one more particle/locator to mark the up vector for the crate to follow. Alex used the ‘getParticleAttr -at worldPosition fooShape.pt’ where foo is the shape node of the particle, to connect the translate to the locators. This method makes a 3-node spring camera possible, which means we can parent whatever we want to the camera. The ropes are just soft bodies.
A bridge connected by ropes would be naturally created using springs. He connects (with set exclusive on) the ends of the softbody cube duplicated from the plank to each other, make the 3 locator system that follows the particles on the soft body plank, repeat for all planks by using duplicate upstream graph (turning off the connecting springs and gravity field, while updating the expressions), and the planks are ready. The ropes are softbody springs with goals that have clusters of vertices parented to the plank/pole near it.
The final example is a character walking across the bridge. It is done simply with 2 planes that pulls the planks on each side using springs and timed with the walk of the character.