I've been asking questions about quaternions over the last couple of

days, and I've got a lot of useful answers, (thank you to those people

who responded)

BUT!

I'm still not sure how to solve the following problem:

If I have a unit quaternion Q, defined which gives me an

orientation of an object. I have a unit axis of rotation vector R,

that I wish to rotate the object around, (by a given angle A).

What is the Quaternion, Qnew, giving the final, rotated position of

the object?

I thought it might be

Qnew = BQB'

Where B = (cos(A/2), sin(A/2)R), and

B' is the inverse of B = (cos(A/2),- sin(A/2)R)

And where the Quaternion multiply operates as follows:

AB =(AsBs -Av.Bv , AsBv+BsAv+AvxBv)

But I tried this, and It didn't seem to give sensible results.

What am I doing wrong?!

Thanks for any help,

Jim Williams