Recipe 50: Branching
General Principles
Animating OpenGL objects
Using audio to drive motion
Working with jit.path for smooth motion
Commentary
After the RoboMoves recipe, I wanted to try a slightly more complex structure and work with a simple audio responsive motion control. The repeated, branching structure of a tree provides the basis for this animation patch, and we use the amplitude of an incoming audio signal to scrub around the animation. While this recipe follows much of the same structure as RoboMoves, the effect of this is really different.
Ingredients
jit.path
jit.anim.node
jit.gl.light
jit.gl.material
jit.gl.gridshape
Technique
First, we'll look at the structure of the animation nodes. To create the tree, I created a repeated branching pattern with each parent node having 2 child nodes. By scaling the each jit.anim.node, we get a structure where the children keep getting smaller as we go down the hierarchy. The nice thing about this sort of repeated branching structure is that it was mostly just duplicating and connecting objects to get it set up. If you wanted to make it even more complex, all you need to do is add in another layer or two of branching children.
To animate the tree, we use jit.path, just like in RoboMoves, but instead of a looping counter, we have a peakamp~ object driving the eval message. The bline is there to smooth out the transitions and make it a little less hectic looking.
by Andrew Benson on April 26, 2012
