Transformation
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Where can I get information as to the meaning of each variable in a SU components transformation matrix? Starting at [0], I think that [9], [10], and [11] are the component's origin.x, origin.y, and origin.z coordinates in the model. Where can I find a lay-person's description of, or can someone tell me what the other values stand for?
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Yeah, Martin just recently put together something of a tutorial on this. Maybe in the last 3 weeks and posted it here. Search for it and it should help.
But essentially you got the location info correct. The last element in the array is a global multiplier for elements 0,1,2,4,5,6,8,9,10. It should be left at 1, but it gets changed sometimes unfortunately.
Then those 9 listed elements above are the rotation and scale of the transformation. 0,1,2 are the x vector, 4,5,6 are the y vector and 8,9,10 are the z vector.
But Martin explains it much nicer than that, if you can find the link.
Chris
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Thanks Chris, my guess for the first 9 elements was that, and I will look for Martin's post. Not good being mathematically imparted, however if you ask me to draw
as follows (doing from memory, hope it's right):[0] [1] [2] [12]
[3] [4] [5] [13]
[6] [7] [8] [14]
[9][10][11][15]where 0, 1, 2 are the x vector, 4, 5, 6 are the y vector, 6, 7, 8 the z vector, 9, 10, 11 the component origin in the model, 12, 13, 14 are user variables, and 15 is essentailly 1. Can I actually put stuff in 12, 13, and 14?
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Honolulu, I think the matrix should look like this:
[0][1][2][3]
[4][5][6][7]
[8][9][10][11]
[12][13][14][15]I think it lines up in rows not columns. And for sure elements 0,4,8 are the starts (the x length) of each axial vector (not elements 0 3 and 6 like you have shown).
Chris
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Chris, Opps, you are right. Thanks.
Martin, Thanks for the link.
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@chris fullmer said:
[0][1][2][3]
[4][5][6][7]
[8][9][10][11]
[12][13][14][15]Yes. OpenGL and SketchUp use row-major order. Microsoft's DirectX (and Fortran!) use column-major order.
@honoluludesktop said:
[0] [1] [2] [12]
[3] [4] [5] [13]
[6] [7] [8] [14]
[9][10][11][15]Odd mistake, that. In that order you can extract the 3x3 array from the 4x4 array in almost no clocks. Any idea where that might have come from, Honolulu?
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I was drawing the matrix from memory of a screen dump the night before and thought elements [9], [10], and [11] were the component's origin. So I tried to make that fit the illustration of your matrix, and erroneously guessed at the order:-)
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I was drawing the matrix from memory of a screen dump the night before and thought elements [9], [10], and [11] were the component's origin. So I tried to make that fit the illustration of your matrix, and erroneously guessed at the order:-)
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