AndrewJJ

06-01-2002, 12:00 AM

Hi,

I'm looking for advice / solution to a fairly minor problem that my tired

brain can't figure out. I need to rotate an object from a rotational vector

(xs, ys, zs) to a target vector of (xd, yd, zd) in incremental steps to

achieve animated rotation. My initial solution was simply to subtract one

vector from the other and divide the result by a factor that determined the

number of rotational increments. Now all worked but I noticed that there

were occasions when an object would rotate through a larger angle than was

needed.

If you consider an object with an x rotation of 270 and you want it to

rotate to 0 then my result requests a rotation of -270 whereas 90 degrees

would have been the quicker move ! I'm looking for a general solution that

provides me with the minimum solution and copes with all angles i.e. -90 is

the same as 270 as is -180 and 180 ...

(I can't believe that I can't get my head around this one ... especially

after deriving a Quaternion based camera class !)

I look forward to hearing from you ...

Many thanks

Andrew

I'm looking for advice / solution to a fairly minor problem that my tired

brain can't figure out. I need to rotate an object from a rotational vector

(xs, ys, zs) to a target vector of (xd, yd, zd) in incremental steps to

achieve animated rotation. My initial solution was simply to subtract one

vector from the other and divide the result by a factor that determined the

number of rotational increments. Now all worked but I noticed that there

were occasions when an object would rotate through a larger angle than was

needed.

If you consider an object with an x rotation of 270 and you want it to

rotate to 0 then my result requests a rotation of -270 whereas 90 degrees

would have been the quicker move ! I'm looking for a general solution that

provides me with the minimum solution and copes with all angles i.e. -90 is

the same as 270 as is -180 and 180 ...

(I can't believe that I can't get my head around this one ... especially

after deriving a Quaternion based camera class !)

I look forward to hearing from you ...

Many thanks

Andrew