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Formula to calculate rotation

  1. Oct 29, 2012 #1
    I'm working with 3D applications, and I'm trying to figure out how to calculate the rotation of x number of points between two points.

    I've made a video to illustrate what I mean:

    So the thing is, I need to find some kind of formula that calculates the rotation of the red points based on the rotation of the green ones. The middle red point should always be 50% between the top and the low point, but the red points below and above the middle should bias the rotation towards their closest green point. In this case I have 5 red points, it would be awesome if the formula also worked on more points.

    So the formula has to work only from knowing the number of red points, and the rotation of the upper and lower green point.

    I'm sorry if this is stupidly simple, but I can't seem to wrap my head around it.
  2. jcsd
  3. Oct 29, 2012 #2
    The middle red point seems to be just the average of the two green points, so that's easy. As for the other red points, unless there's some complexity I'm missing, you could probably just take them to be the weighted average of the rotation of the middle red point and the nearest green point; the weight will determine how biased it is towards the green point.
  4. Oct 29, 2012 #3
    Thanks for your reply :)

    That could work, however I'm limited to my 3D-application's native math-nodes (Autodesk Maya), and it doesn't seem to have a node that can do a weighted average operation. It has an average node, but not a weighted average node.

    I'm sorry I forgot to say that in the first post, the math-functionality I can use is limited to these:
    Plus, Minus, Avarage, Multiply, Divide, Power, Compose Matrix, Decompose Matrix, Transpose Matrix, Inverse Matrix, Vector Product
  5. Oct 29, 2012 #4
    If you can add, multiply and divide, you can compute a weighted average.
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