math: sline lope

i need to draw an imaginary line in a 3D world using the slope
method. (terminology is off. been a few years since math class)

if i remember right its the difference of x over the difference of y.
(X1 - X2 ) / (y1 -y2) used to calculate any point on a straight line.

in short im trying to find a way to use this in a 3d world for collision detection(GuNs – path of the bullets/projectiles).
any links would be a big help.
thx

Quote:

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if i remember right its the difference of x over the difference of y.
(X1 - X2 ) / (y1 -y2) used to calculate any point on a straight line.

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its y's over x's

(y2-y1)/(x2-x1)

at least thats how ive been doing it on all my homework hehe...

y2-y1/x2-x1
thats the slope formula

Quote:

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y2-y1/x2-x1

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(y2 - y1) / (x2 - x1)
is more accurate. Remember the order of operations :)

....

Code:

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∆Y
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 ∆X

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what is ∆ ?

∆ means delta. Delta means difference. Therefore, ∆y means difference in y.

anyone know where i can squeeze 'z' into this equation?
googles doesnt have much on the subject

http://www.univie.ac.at/future.media...om1/geom1.html
is the only place that has what i want but they dont show the math

If you're working in 3D, you need to be using a plane equation, not just slope intercept.

so does an equivalent of 'slope' exist for 3d? I kind of thought it would be:
deltaz/(deltay/deltax)

but it seems pretty much useless anyway, if it exists.