Math and Art: Math and Computer Animation

This is a clear, concise, and fascinating overview of how some very advanced mathematical ideas are making their way into 3-D animation.

http://www1.ams.org/samplings/feature-column/fcarc-harmonic

Here’s the basic setup.   In order to efficiently model a character, you approximate it with a frame that is built around a few important points.  To move the character, you focus on moving just those points that define the frame.  Thus, moving the character from point A to point B boils down to understanding where those handful of crucial points go.

The tricky part is figuring out a way to smoothly bring all those in-between points along for the ride, and that’s where the math comes in.  The secret is to think of those in-between points as averages of the points that define the frame.  The article explains how barycentric coordinates, harmonic functions. and a surprising amount of calculus are being used to pull off this movie magic!

Math and Art: The Art of the Ellipse

This is a cool article about how important the ellipse is to the artist.

http://opinionator.blogs.nytimes.com/2010/09/23/the-frisbee-of-art/

The author gives a nice, if long, explanation about the significance of the ellipse, but it basically boils down to this:  circles are everywhere. And often, when we are looking at circles, we’re looking at them atilt.  We see projections of the circle, and projections of circles are ellipses.

Think of it this way:  suppose you have a hula hoop and you hold it parallel to the ground.  The shadow you see is circular, but if you tilt the hula hoop, the shadow will change–into an ellipse.  I don’t have a hula hoop, so I made do with a spare key ring:

As the circular key ring is rotated, it becomes less parallel to the ground; the shadow becomes less circular and more elliptical.  And at the end, the ellipse vanishes–an ellipse eclipse!

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