# angular speed implementation

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Hello, Let say we have a cube with (pi/4,pi/4,pi/4) as orientation vector. Now, (due to some collision, for instance), I have to apply a y-axis rotation speed, so that the cube should be rotating along y axis. This angular vector , according to angular speed vector and elapsed time has the form (0,lambda,0) The problem is if I add orientation and angular vectors, I have (pi/4,pi/4+lambda,pi/4). So the cube isn't rotating along Y axis, but along transformed Y axis according to the first applied rotation(s). ( In my case, X axis rotation). Should I keep an additional parameter per object, let's say angle, and apply 2 series of rotations (one for orientation, one for angles) for computing world matrix ? Or, am I totally wrong and should I simply add angular vector with orientation ? If so, could you explain what's wrong in the explained idea? Thank you !

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Quote:
 Let say we have a cube with (pi/4,pi/4,pi/4) as orientation vector.
What do you mean, "orientation vector"? Are you trying to maintain the cube's orientation as a set of Euler angles? That's a tedious thing to do, and probably confers no benefits.

Maintain orientation as a quaternion or as a matrix. Applying a rotation is simply a matter of multiplication.

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I meant pi/4 angle along X,Y and Z axis

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In other words, you're applying the three angles separately, as successive axial rotations. That's Euler angles. (Or, to be more pedantic, Tait-Bryan angles.) It's a representation of orientation that's easy to understand, but it doesn't work well for actually maintaining combined rotations.

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Thank you Sneftel
I 'll have a look on Euler angles

;-)

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That is the opposite of what I said to do. Euler angles aren't the right representation here; check out more suitable representations. This has a fair amount of useful information.

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