103 reputation
2
bio website
location
age
visits member for 2 years, 8 months
seen Dec 17 '12 at 15:21

Nov
19
awarded  Popular Question
Dec
16
asked simple rectangle collision
Feb
14
awarded  Scholar
Feb
14
accepted Projecting a point onto a vector (2D)
Feb
14
comment Projecting a point onto a vector (2D)
The final projected point of (4, 5) on vector (1, 2) is (2.8, 5.6). Thanks for your help, I believe that I understand the concept now. I was a little confused by the short "Mathematics" section of this tutorial: content.gpwiki.org/index.php/… . I'm not sure, but it seems like it might have incorrect information.
Feb
14
comment Projecting a point onto a vector (2D)
( (4 * (1 / sqrt(5)) + (5 * (2 / sqrt(5)) ). In the end, the projected point would be equal to that dot product multiplied by the normalized vector, or: ( (4 * (1 / sqrt(5)) + (5 * (2 / sqrt(5)) ) * (1 / sqrt(5), 2 / sqrt(5)). Is this correct?
Feb
14
comment Projecting a point onto a vector (2D)
Thanks for your detailed reply. I forgot to mention a critical point in my original post - the vector that the point will be projected onto will have been normalized. Based on your formula above, it looks as though the formula reduces to (a⃗ ⋅ b⃗) b⃗. That is, the dot product of a and b multiplied by vector b. Is it possible to go through an example? Let's say I have a point (4, 5) and I want to project it onto the vector (1, 2). First, I would normalize the vector: sqrt(1^2 + 2^2) = sqrt (5). The normalized vector would be (1 / sqrt(5), 2 / sqrt(5)). The dot product would be:
Feb
13
asked Projecting a point onto a vector (2D)