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finding the angle

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Hello I have my camera located at (x,y,z), and looking at the direction (x1,y1,z1). If i have a model at (x2,y2,z2), how do i find the angle between the model(x2,y2,z2) and my camera(x,y,z) ??? thanks , Bruno

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The short answer is to use the dot product.

But please, use the search feature to find "angle between two vectors". It will be more detailed.

Thank you,

Cédric

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your three points define a triangle. Use the law of cosines:

a2 + b2 - 2ab cosA = c2

where A is the angle between sides a and b. so, in your case, you want to know a, so you rewrite the equation:

(a2 + b2 - c2)/2ab = cosA
arccos((a2 + b2 - c2)/2ab) = A

a2=dx12 + dy12 + dz12

b2=dx22 + dy22 + dz22

dx1 = x1 - x
dy1 = y1 - y
dz1 = z1 - z
dx2 = x2 - x
dy2 = y2 - y
dz2 = z2 - z

check the time on my post. If it is more than 10 minutes old, then I don't have any corrections pending.


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[edited by - capn_midnight on September 2, 2003 4:05:21 PM]

[edited by - capn_midnight on September 2, 2003 4:09:02 PM]

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