Thread Subject:

Find vector perpendicular to axis A and through point B

I have an axis A, with normalized directional vector d=[ 0.0994 0.2237 0.9696] and positional vector O=[1 1 1]. Now I have a point in space R1= [0.0905 -3.7694 2.1939]. How do I calculate the vector which is perpendicular to the Axis and through R1 with Matlab?

"Els " <y.e.t.reeuwijk@student.utwente.nl> wrote in message <hudltp$6ai$1@fred.mathworks.com>...
> I have an axis A, with normalized directional vector d=[ 0.0994 0.2237 0.9696] and positional vector O=[1 1 1]. Now I have a point in space R1= [0.0905 -3.7694 2.1939]. How do I calculate the vector which is perpendicular to the Axis and through R1 with Matlab?

Hi, I'm not sure about your terminology "positional vector", but see

>>doc cross

to see how to compute the cross product of two vectors in 3-space.

Wayne

Wayne, the directional vector is the slope of the axis. And the axis/line starts at the positional vector. The difficulty is that I do not know on which point of the axis/line the angle with point R1 is 90 degrees and thus perpendicular. Or can this be calculated with cross as well?

Best wishes,

Els