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I've got a 2D projectile code sample working, but would like to extend it to 3D. How would I calculate the initial velocity of the Z-axis? At the moment, I've got:

initVel.X = (float)Math.Cos(45.0);
initVel.Y = (float)Math.Sin(45.0);

How would I convert this to work in 3D, and add the initial velocity for the Z-axis?

In my example, X is across, Y is up down and Z is going into the screen. I also normalize the vector and multiply it by the speed.

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Although you have a trigonometric answer below, if you intend to dive deeper into 3d, you might want to consider trading in the trigonometric approach to 3d problem solving in favor of a linear algebra approach... Much less headache and much more versatile in the long run. –  Steve H Mar 6 '11 at 22:21
Thanks for the suggestion. I'm using vectors to perform the motions, but since I only need to call this very few times, I figured it would suffice. To clarify, by a linear algebra approach, do you mean using Matrices and Quaternions? –  Skoder Mar 6 '11 at 23:35

1 Answer 1

up vote 3 down vote accepted
double ZAdjust = Math.Cos(XZAngle);
initVel.X = (float)(Math.Cos(XYAngle) * ZAdjust);
initVel.Y = (float)(Math.Sin(XYAngle) * ZAdjust);
initVel.Z = (float)Math.Sin(XZAngle);
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Thanks for the help. –  Skoder Mar 6 '11 at 19:43

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