Easing script

  • On 11/02/2018 at 05:37, xxxxxxxx wrote:

    Hi everybody, I'm trying to add an ease-in expression to a rig. I'm not really a math guy, so I'm referencing Penner's equation and in particular this doc: http://upshots.org/actionscript/jsas-understanding-easing.

    My code for testing looks like this so far:

    import c4d, math
    #Welcome to the world of Python
    start = 10   #start pos
    end = 300    #end pos
    d = 50       #duration
    def easein(t,d) :
        ratio = t/d
        print "ratio: ",ratio
        return math.pow(ratio,5)
    def main() :
        t = doc.GetTime().GetFrame(doc.GetFps()) #current frame
        factor = easein(t,d)
        out_pos = start + (end-start) * factor
        print "t: ", t
        print "d: ", d
        print "factor: ", factor
        print "out pos: ", out_pos

    but the result of (t/d) is always 0.0. I guess is something with the values type but I can't figure it out.
    What am I doing wrong?

    Thanks for any advice or help!

  • On 12/02/2018 at 01:49, xxxxxxxx wrote:


    you are calculating the ratio as an integer division. Simple solution, either make d a float value (d = 50.0) or force the division to be calculated with floating point (ration = float(t) / float(d)).
    Here's some information on Floating Point Arithmetic in the Python docs.
    Please also note, Cinema 4D use a 2.7.x implementation of Python. There is a change in behavior of integer division compared to Python 3.x, see for example here.

  • On 12/02/2018 at 12:21, xxxxxxxx wrote:

    Ahh, that makes sense. Thanks for the help!

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