edit: This thread might need moved, sorry about that.(adsbygoogle = window.adsbygoogle || []).push({});

Hi, I have ended up on this site a few times after searching various maths issues; it seems to have a good community so I am asking you good people for a little help understanding this.

Tomorrow I have a semi-important maths exam, if I fail it I can resit in 2010 but I would of course rather not have to do that. I am studying game design, so I shall be needing maths a lot more soon.

I missed the part that involved the mathematics of projection, so I need to figure this out fast.

Reading the materials I understood fairly well until it bluntly proposed a problem without before giving a solution to a similar one, so I need a bit of help.

The problem is as follows:

Calculate the orthogonal projection of the points A(3,5,1) and B(-4,2,6) onto the plane -2x+4y-z=3 and determine the equation of the line joining the image points on the plane.

I understand visually what is going on here, but I don't know where to start. The notes talk about the Par i/j/k matrices (none seem to apply here) and the homogeneous coordinate transformation matrix... now I could plug numbers in and see what I come up with, its not like I am going to run out of paper. But I am scared to get lost in this.

Who can help walk me through this? It may take a few posts ^_^

edit:

OK, I think I need to start with:

vector n = (-2,4,-1)

n being the normal

brackets should be vertical... but I don't know how to format it that way

edit:

Ok, I have got this far:

-2(3-2t)+4(5+4t)-(1-t)=3

correct so far? I filled in the values for p=r+tn

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Orthogonal projection of 2 points onto a plane

**Physics Forums | Science Articles, Homework Help, Discussion**