Advertisement Jump to content
Sign in to follow this  

Rotational speed

This topic is 2596 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

hello every one.

I am trying to make a collision response in 3D, and that includes rotation. I know that rotation is a vector quantity, but I don't know how to use such a vector.
if the vector is [2,6,7], should I rotate the object 2 radians around the X-axis, 6 radians around the Y-axis, and 7 radians around the Z-axis?

Share this post

Link to post
Share on other sites
Ah. In that case, you treat the center of mass as a particle in 3D space. To quote Wikipedia's Particle in three dimensions subsection:

"The angular velocity in this case is generally thought of as a vector, or more precisely, a pseudovector. It now has not only a magnitude, but a direction as well. The magnitude is the angular speed, and the direction describes the axis of rotation."

in the case of [2,6,7]

sqrt(2^2+6^2+7^2) = 9.43 radians per second, which is very close to 3 rotations per second.

[2,6,7]/9.43 = [0.21, 0.63, 0.74]

So the object is doing about 3 rotations per second clockwise on the [0.21, 0.63, 0.74] axis.

edit: I forgot to comment on the direction of rotation.
The rotation is always clockwise. To get a counter-clockwise rotation about a given axis, make a rotation about the negative of that axis.
For example, 3 counterclockwise rotations per second about the [0.21, 0.63, 0.74] axis would be expressed as [-2,-6,-7].

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement

Important Information

By using, you agree to our community Guidelines, Terms of Use, and Privacy Policy. is your game development community. Create an account for your GameDev Portfolio and participate in the largest developer community in the games industry.

Sign me up!