Author Archives: ian

Straight Line Curves

For the past week or so I’ve been obsessed with the following party trick that I used to use to keep my kids entertained in Italian restaurants.¬†Flip over your paper placemat and grab a pencil. Draw a straight line from … Continue reading

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Constructing a Rotation Matrix From Basis Vectors

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Geometric Primitives Lectures

I’m going to be out of town on September 27-30, 2011 presenting two papers at GAMEON-NA, so here are videos of the lectures that I would have given to my Game Math and Physics class at the University of North … Continue reading

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Gimbal Lock

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Composing Rotations

Here’s why programmers don’t need to remember the details of rotating around an arbitrary axis: Rotations are closed under composition. All you need to do is compose rotations around the object’s cardinal axes.

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Vectors Just Want To Be Free

Remember, while we may draw vectors at a particular position (for example with their tails at the origin), they really don’t have a sense of place. All they have is a magnitude and a direction. If you’re unclear on the … Continue reading

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Lecture Notes Being Alpha Tested

I have lecture notes for all except the last 3 chapters, but I’m not quite ready to release them yet. I’m alpha-testing them in my Game Math and Physics class (see http://larc.unt.edu/ian/classes/fall11/csce4215/) to make sure that they’re just right. More … Continue reading

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