Re: Animation of rotating axes

Brad Cooper wrote:

The angular velocity of the xyz system relative to the XYZ system is given
by w = 2ti - t^2j + (2t+4)k where t is the time.

I'm afraid you lost me here. Are you referring to quaternions operating on homogenuous coordinates?

Next, I need to use plot::Rotate3D to rotate this whole system with angular
velocity w = 2ti - t^2j + (2t+4)k

plot::Rotate3d rotates objects around an axis. If I read your description correctly, you would need to calculate that axis first, which would be a waste of time, given that Rotate3d calculates a matrix from the axis and angle. You might be better off using plot::Transform3d, which takes a 3x3 matrix A and a 3-element vector b to transform x to A*x+b. (Note: 3.0 used A*(x+b), which was considered a design bug.)


regards,
	Christopher
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