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johnnyBravo

3D maths, finding x,y,z from angles/axis rotation

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You know in 2D how you can work out the x,y from the angle and distance . That is what I want to do in 3d. But there are a few little things that I am confused about. First to get the angle of the 3 different axises, is it like this?: x axis = using z and y planes to calculate? y axis = using z and x planes to calculate? z axis = using x and y planes to calculate? if so, can I work out the x point from either the calculations of the y or z axis and so on for the y and z points ? Thanks, [edited by - johnnyBravo on January 6, 2004 2:08:48 AM]

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In 2D, from a yaw angle and a distance you can calculate X and Y. This is basically a conversion from polar coordinates to Cartesian coordinates.

In 3D, you have two angles and a distance - these two angles are yaw and pitch - that define an (X,Y,Z) point. Yaw is the same as it was in 2D. But pitch is the "upward" angle into the Z dimension that didn't exist in 2D.

First, use the XY planes to define a 2D coordinate system, and use the yaw angle to generate X and Y values (same math you used in 2D). For the pitch, use the XZ plane as a 2D coordinate system, and use the same math you did to find the X and Y coordinates before. But this time around, the Y value you find is really the Z value. So you have the X and Y coordinates you find with the yaw, and the Z coordinate you find with the pitch. Make this into a vector, normalize it, and multiply by the distance. You now have the point you want.

[edited by - Zipster on January 6, 2004 5:18:02 AM]

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It depends what you''re doing. If you''re trying to find a 3D vector from given angles, then you only need the 2 angles like he said. (and distance obviously)

If you''re working with a camera or object then roll might be used too, though it''s not usually.

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