3d to 2d mapping

Discussion in 'Java' started by Miguel De Anda, Jun 27, 2003.

  1. I'm trying to write a little script that draws dots into a 3d space. It is
    very small and has only 30 dots (5 by 6). These dots are on fixed x, y
    positions but I need to position them on various z positions. I want to make
    the z axis to be vertical (on the screen) and the x to be to the right (and
    down a little bit) and the y to be back into the screen (and right a little
    bit). I took a linear algebra class that covered how to do such
    transformations but my brother has the book right now. Can anybody help me?
    I simply need some matrix or something that I can multiply my [x, y, z] by
    to get my new [x, y] positions that would appear to be in 3d on the screen.
    This is just going to be for a demo that I need to do. Thanks.
     
    Miguel De Anda, Jun 27, 2003
    #1
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  2. Miguel De Anda

    pete kirkham Guest

    From a quick google,
    http://pages.infinit.net/jstlouis/3dbhole/mathematics_of_3d_graphics.html#Transformations
    has some sample transformation matrices which will do.

    Take your 3d point, translate and rotate so the translated x and y axes
    align to your screen x and y (eg: rot X 90, rot Y ~10, rot X ~10 for Z
    up, X right and down a bit, translate by <[screen-width - mean
    X]/2,[screen-height - mean Y]/2, [distance-to-eye + lowest-z]> will give
    about what you describe) , then (optionally) divide by the transformed z
    value for perspective, not plottin all points whose z-values are greater
    than the distance from the eye to the screen.

    Pete
     
    pete kirkham, Jun 27, 2003
    #2
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