wrong results when rendering using fields within a python effector

[TSD]

Hello, I've got a problem using the Clone object with a Python Effector that uses a field. I hope this is the right subforum for this kind of problem.

The Python-Code:

md = mo.GeGetMoData(op)
fall = md.GetFalloffs()
print("fall "+str(fall))

In the Editor it returns a number like it should, but when I render it always returns 0.0. I've attached the C4D File including a screenshot. I'm using the latest C4D Version 2024.3.2

Python-Effector-problem_0001.c4d

[m_adam]

Hi thanks for reporting it, this will be fixed in an upcoming release (not necessary the next one).

As a workaround you can sample the field yourself like so:

import c4d
from c4d.modules import mograph as mo
#import redshift

def CustomGetFalloffsForFields():
    md = mo.GeGetMoData(op)
    mdcount = md.GetCount()

    # Prepare FieldOutput
    flags = c4d.FIELDSAMPLE_FLAG_VALUE
    outputs = c4d.modules.mograph.FieldOutput()
    outputs.Resize(mdcount, flags)
    
    # Prepare FieldInputs values
    mdmat = md.GetArray(c4d.MODATA_MATRIX)
    positions = [matrix.off for matrix in mdmat]
    normals = [matrix.v3 for matrix in mdmat]
    uvws = md.GetArray(c4d.MODATA_UVW)

    callerMG = gen.GetMg() if gen and gen.IsInstanceOf(c4d.Obase) else Matrix()
    inputs = c4d.modules.mograph.FieldInput(positions, len(positions), callerMG)
    
    # Prepare FieldInfo values
    callerStack = c4d.modules.mograph.FieldCallerStack()
    callerStack.Add(gen)
    
    infos = c4d.modules.mograph.FieldInfo()
    infos._flags = flags
    infos._callerThread = c4d.threading.GeGetCurrentThread()
    infos._doc = gen.GetDocument()
    infos._callerStack = callerStack
    infos._inputData = inputs
    
    # Sample the field
    op[c4d.FIELDS].SampleList(infos, inputs, outputs)

    return outputs._value

def main():
    md = mo.GeGetMoData(op)
    if md is None: return False

    cnt = md.GetCount()
    
    fall = CustomGetFalloffsForFields()
    print("fall "+str(fall))

    for i in range(0, cnt):
        if fall[i] > 0:
            print("################## YES!!! IVE FOUND A PRODUCT!!!")
            return True
    return True

Cheers,
Maxime.

[TSD]

Hi Adam, thanks for the update and the workaround!