Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

In the section, Inverse Kinetics in 2D of this article: http://freespace.virgin.net/hugo.elias/models/m_ik.htm

enter image description here

There is Vector R. How could I find this vector R? I know the length of the bone and its angle, how could I then calculate vector R in this example?

Thanks

Would it simply be taking the vector of the angle and returning v.y, -v.x?

share|improve this question

1 Answer 1

up vote 1 down vote accepted

The base of the vector $R$ is just $(L\cos(\theta),L\sin(\theta))$ where $L$ is the length of the bone and $\theta$ is its angle, usually measured from horizontal to the left. If the desired length of $R$ is $r$, the offset is $(-r\sin(\theta),r\cos(\theta))$, so the end point is $(L\cos(\theta)-r\sin(\theta),L\sin(\theta)+r\cos(\theta))$ . Is this what you are after? I don't see anything to set $r$ in the problem.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.