# stuck again (cross product)

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HI! Let's say I have the following equation to be fulfilled: Vector(collison normal) X (MF*Vector(a)+LF*Vector(b)+TF*Vector(c)) = Vector(0) Now, I know : Vector(collision normal) Vector(a) Vector(b) Vector(c) MF So I'm looking for LF and TF. That makes three equations (cross product) for two variables. Here's what I did: -I replaced the ZERO on the right side of the second equation with the left side of the third equation -solved that new equation (2) for LF and set that LF into the first equation -out comes TF -TF into (2) gives me LF (done!) SOMETHING WRONG ??? (don't start to outwright things! They tend to explode!)

write

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Ncoll x (MF * a + LF * b + TF * c) = 0
MF * (Ncoll X a) + LF * (Ncoll x b) + TF * (Ncoll x c) = 0

LF * (Ncoll x b) = MF * (a x Ncoll) + TF * (c x Ncoll)

LF * [(Ncoll x b) . (Ncoll x b)] = [MF * (a x Ncoll) + TF * (c x Ncoll)] . (Ncoll x b)

LF = [MF * (a x Ncoll) + TF * (c x Ncoll)] . (Ncoll x b) / [(Ncoll x b) . (Ncoll x b)]

LF = [alpha_vector + TF * theta_vector] . [beta_vector]

alpha_vector = MF * (a x Ncoll)
theta_vector = (c x Ncoll)
beta_vector = (Ncoll x b) / [(Ncoll x b) . (Ncoll x b)]

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gee! half of those vector operations you just did, I haven't even seen yet.

so I guess:

LF = [alpha_vector + TF * theta_vector] dot [beta_vector]

gives me the one equation I wanted. BUT where do I have to put LF into in order to get TF? What is my second equation?

thanx, man! I didn't expect anyone to help me that far :)

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