Drive smooth rotation

PMenich

Hey, I've been trying to create a python node in xpresso to emulate this bit of code from the amazing Mr Ebberts...

http://motionscript.com/articles/speed-control.html

Here's the After Effects expression I'm trying to translate...

spd = effect("Slider Control")("Slider");
n = spd.numKeys;
if (n > 0 && spd.key(1).time < time){
  accum = spd.key(1).value*(spd.key(1).time - inPoint);
  for (i = 2; i <= n; i++){
    if (spd.key(i).time > time) break;
    k1 = spd.key(i-1);
    k2 = spd.key(i);
    accum += (k1.value + k2.value)*(k2.time - k1.time)/2;
  }
  accum += (spd.value + spd.key(i-1).value)*(time - spd.key(i-1).time)/2;
}else{
  accum = spd.value*(time - inPoint);
}
value + accum

Here's where I'm at with my Python translation...

from typing import Optional
import c4d

op: c4d.modules.graphview.GvNode # The Xpresso node
doc: c4d.documents.BaseDocument # The document evaluating this node
tp: Optional[c4d.modules.thinkingparticles.TP_MasterSystem] # Particle system

def main():
    global Output1
    #Grab the host-object to the xpresso Tag
    Rect = op.GetNodeMaster().GetOwner().GetObject()

    #Get the UserData
    spd = Rect[c4d.ID_USERDATA,1]

    # Get the first animation track of the object
    track = Rect.GetFirstCTrack()

    # Get the animation curve of the track
    curve = track.GetCurve()

    # Get the number of keyframes on the curve
    n = curve.GetKeyCount()

    fps   = doc.GetFps()
    sFrame= doc.GetMinTime().GetFrame(fps)
    eFrame= doc.GetMaxTime().GetFrame(fps)
    name  = op.GetName()
    key = curve.GetKey(1)
    keyValue = key.GetValue()
    keyFrame = key.GetTime().GetFrame(fps)
    currentFrame = doc.GetTime().GetFrame(doc.GetFps())
    value = spd


  
    if n > 0 and curve.GetKey(1).GetTime().GetFrame(fps) < currentFrame:
        accum = curve.GetKey(1).GetValue() * (curve.GetKey(1).GetTime().Get() - sFrame)
        for i in range(2, n):
            if curve.GetKey(i).GetTime().Get() > currentFrame:
                break
            k1 = curve.GetKey(i-1)
            k2 = curve.GetKey(i)
            accum += (k1.GetValue() + k2.GetValue()) * (k2.GetTime().Get() - k1.GetTime().Get()) / 2
        accum += (curve.GetValue(curve.GetKey(i-1).GetTime()) + curve.GetKey(i-1).GetValue()) * (currentFrame - curve.GetKey(i-1).GetTime().Get()) / 2
    else:
        accum = Input1 * (currentFrame - sFrame)
    
    print(Input1 + accum)

    Output1 = value + accum

There are loads of unnecessary variables in there btw - that was me just trying to figure this stuff out!

Basically trying to drive rotation without using time as my driver. Now, I'm no programmer (as you'll soon find out!), but the attached project does work, but doesn't do what I want it to! When the UsrData 'speed' gets to 0 it should stop. And the rotation is meant to be smooth ramp up and then smooth ramp down.

Any python geniuses out there got time to take a look and tell me where I'm going wrong?

Smooth_Rotater.c4d

m_adam

Hi @PMenich first of all welcome to the plugincafe forum.

If you want to embed code in your topic you should use the code markup which consist of 3 `. So you need to do ``` Your Code ``` this way your topic will be more readable, Ferdinand did cleanup your topic.

Regarding your initial question, I would like to let you know this is out of scope of Maxon support according to our Forum and Support Guidelines and we cannot debug your code for you, so it will be up to the community to provide an answers.

Cheers,
Maxime.

jana

Hello @PMenich ,

without further questions or postings, we will consider this topic as solved by Friday, the 11th of august 2023 and flag it accordingly.

Thank you for your understanding,
Maxon SDK Group