j00ey 11 Report post Posted May 1 I'm having a little difficulty with some matrix maths. I have 3 points P0, P1 and P2 [as in the attached drawing] and I need to find the point on the line between p0 and p1, such that the line from it to P2 is perpendicular to it. The way I tried is to first find the angle between P0-->P1 and P0-->P2 [acos of the dot product], then from there find the lengths a, o and a using trig, from there it's simple to find the correct position but somewhere or other I'm going wrong. I'll persevere but I wondered if there is some standard function to find that position, I imagine it must be a common thing to want to do... Thanks in advance Share this post Link to post Share on other sites

j00ey 11 Report post Posted May 1 I figured it out, I had a plus instead of a minus... Share this post Link to post Share on other sites

Varishtraheja 0 Report post Posted July 28 Hey is it possible for you to attach your hip file for me too see how you did it? Thank you. Regards Varisht Share this post Link to post Share on other sites

j00ey 11 Report post Posted July 31 (edited) I don't have that particular file to hand any more but I made you a file to demonstrate an easier method. If you take the dot product of the normalized vector P0->P1 in the drawing above, and the UNnormalized vector P0->P2 that will give you the magnitude of the vector in the (normalized) direction P0->P1 that the perpendicular projection point is. That's probably a bit garbled but if you look at the file I hope it will make sense... projection.hip Edited July 31 by j00ey Share this post Link to post Share on other sites