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Posts tagged ‘Harmonic Oscillation’

Rigging retrospective (part one)

August 20, 2007

Charles

So Ive been away on vacation over the past two weeks in beautiful Montreal (an amazing city). I had time to think about rigging, ways to break it up and what it is at its heart: intergrating systems.

Rigging can be regarded as modular in one sence and choatic in another. It can also be though of a group of systems that interact with each other in simple and hybrid types of ways. There are three main ‘Driven Systems’ at its heart:

Kinematic – the animator drives the rig with keyframes, purely controlling the puppet and f-curves

Procedural – the animator drives values which adds automatic driven motion, the wave if you will doesnt however have to be procedural and handmade in a fourier synthetic way.

Dynamic – the animator drives controls in which there ‘children’ act in a physically based way. The controls themselves could also act dynamic.

Theses are the bases, but many hybrid versions of these can be combined, waves driving dynamics for instance. A rig should only support this if its really really neccesary – we need to understand what a rig needs. At its heart is what the animator wants, especially interms of control. But we can also make our own assumptions and give some basic rules in constructing a rig:

1. A rig is a series of systems.

This can be a hard idea to understand, but if we treat a part of a rig as a system than a series of joints (more of an outwardly looking in analysis), we can work out what we need. A good example is a tentacle – because were are treating this entirely as a system – e.g. a splineIK base with a layer of FK controls. The tentacle is treated as a whole unit and this is how we should look at it when rigging. Lets break it down:

A tentacle that needs to be fk, dynamic, driven and procedural – we’ll first off we can pair these together fk/procedural and dynamic/driven as a system. By doing this we can see that the fk/procedural can ‘ride’ the dynamic driven system. And this dynamic driven system itself can be treated as one: A dynamic chain solution that rides a bezier spline based on tension, and a fk procedural system that rides this in tern.

A tentacle is essentially an easy example as we regard it as unit, but can this be the same for a wing, leg or even spine? A spine or torso can be summed up as three independant units that are glued together either or additionally by a positon or a main control. It can be regarded as a system. A wing is essentially an arm, that feathers ride along and intern have dynamics (air resistance etc)

Fourier Synthesis and Harmonic Oscillation

July 2, 2007

Charles

So currently im looking into a a scripting language to so I can develop my math stuff outside of the software and keep it a data driven as possible – currently its between JavaScript or Python. All I really care about is class definitions and handling functions.

I’m also looking into fourier synthesis, harmonic oscillations and and analog synthesis as a friend and I have a plan for an interesting tool! 🙂 Should be fun. Im also looking into oscillation and phase shift as a tool for animators – something along the lines of the ‘Wiggly Splines’ Pixars paper – I understand the basics of it, but it gets into territory dealing with basis function and new curve generalizations which in theory is possible but for max I’d either have to write sdk something else.

As to fourier synthesis, it’s really very very powerful as it allows paramaterisation of the wave form, such as quantization, rectify and full-rectifying with relative ease. Phase shift, frequency, amplitude and magnatude (terms of cosine and sine) can be handled in a deterministic fashion. Functions such as high-pass, reverb are a little more complex but if ineffect you controlling just the terms of the synthesis it might be easier.

High/low pass deal with frequency cut-off using two variables: the frequency and the attenuation: a range of q1-q10. I’m still a little confused as to how to affect the waveform as a process of the fourier – but I’m looking into it.