Easing script

Helper

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!
cheers
massimiliano

Helper

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

Hi,

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.

Helper

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

Ahh, that makes sense. Thanks for the help!
Massimiliano