# Matrix Rotations

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Hey, I am having a really annoying problem... I can't figure out how I can get the real Translation of my Matrix, after Translating, Rotating, and then Translating again... So, here's some code example...
Dim Tester As Matrix
Tester = Matrix.Identity
Tester = Tester * Matrix.Translation(0, 0, 5)
' This first message box was correct - (0, 0, 5)
MsgBox(Tester.M41 & "," & Tester.M42 & "," & Tester.M43)
' I Rotate 90 degrees on the Y axsis...
Tester = Tester * Matrix.RotationY(90)
' Then I translate on the Z axis again, which after a 90 degree rotation
' should be equivelent to the old X axis.
Tester = Tester * Matrix.Translation(0, 0, 5)
' Ok, this second message box came up with this... (4.4, 0, 2.7)
' The numbers I was looking for were something like - (5, 0, 5)
MsgBox(Tester.M41 & "," & Tester.M42 & "," & Tester.M43)

I don't know what I am doing wrong... my camera always works, and doesnt have problems... but I just can't get the right Translation... If you could help that would be great! O, and I do plan on using Quaternions soon, but I would like to fully understand Matrices first...

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If you're using the MDX Matrix class, then you need to pass in radians instead of degrees. 90 radians is about 117 degrees, which is consistent with the numbers you're getting.

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Ya.. ur right... I guess thats actually a bad example... well, when im using my camera if i move around a while, and then go close to 0,0,0 ... many times i get numbers that are not even close to that... I don't really understand why... Thanks Though

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It would probably be a good idea for you to look into the theoretical side of matrix mathematics. Simply examining individual elements will only be valid in a few isolated cases - you need to consider the matrix as a whole.

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Ok, thanks... thats basically what I was wondering... I read all about how they work and stuff, but I just never really looked closely at the actyal numbers... I was basically trying to find a way out of using too much math, but I guess I'll use some. Thanks You guys

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