Align Z axis so it is always perpendicular

This may well be a very simple (and simple) question. So I'll apologise in advance. The question in relating to a discussion I had with someone.

Consider the fact that we have 3D orthogonal vector, consider that it may be a time series.

f1 = = [ -0.1408 -0.3257 2.1674]

How would you go about aligning the vector so that it is always perpendicular to Z axis.

Thanks

Answer 1

[Roger Stafford]

Set its third component to zero:

   f1(3) = 0;

Of course that shortens the vector. If you want to preserve its vector length,

   n = norm(f1);
   f1(3) = 0;
   f1 = f1*(n/norm(f1));

[Dan]

Roger,

Once again you've come to the rescue. I'm frustrated that the answer was to simple. I did consider you response beforehand, but I assumed that wasn't the case. Thank you for taking the time to reply.