[SOLVED]A Pulse With Decay?

[Atom]

Hi All,

I am looking for a python or Houdini function that will give me a pulse to 1.0 with a decay every so many frames. So it would kind of be like a modulus integrated with a decay. Does anyone know how to code something like this?

A typical output might look like this...

0.0 0.0 0.0 0.0 0.0 1.0 0.8 0.6 0.4 0.2 0.0 0.0 0.0 0.0

 

Edited August 25, 2016 by Atom

[stevegh]

Why not just write your own? Give it a couple of parameters like start frame, decay amount/time, maybe add a type like linear/quadratic etc. Or you could use SciPy.

[f1480187]

@P.y = chramp("ramp", @Time);

Use a ramp. It will give you an absolute control over the pulse shape.

 

pulse.hipnc

[Atom]

My goal is control the eye blink on a character.

The ramp is an interesting idea, but I still need to feed it a lookup value between 0.0 and 1.0 which needs to be the percentage along the modulus of the blink rate in frames.

node = hou.pwd()
geo = node.geometry()

my_ramp = node.parm("ramp").eval()
n = my_ramp.lookup(0.5)
print n

 

 

 

[Atom]

I guess with a little fixup I think this kind of approach works and I can still use the ramp for shaping the decay of the eye blink.

node = hou.pwd()
geo = node.geometry()

def returnFramesPastLastModulus(current_frame, current_modulus):
    cf = current_frame
    while(cf > current_modulus): cf -=current_modulus
    return cf
    
frame_current = hou.frame()    
blink_rate = 120    #Blink every 120 frames.

f = returnFramesPastLastModulus(frame_current, blink_rate)
v = float(f)/float(blink_rate)
my_ramp = node.parm("ramp").eval()
n = my_ramp.lookup(v)
print n

Thanks for the insight.

Edited August 25, 2016 by Atom