Hello an welcome to the PluginCafe.
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I assume you are using Cinema 4D R20?
Notice that a script is - well - a script. A script is started, executes some command and then finishes. While doing so, Cinema 4D will be blocked. You can use threads to distribute the work done in the script but the script will keep blocking Cinema while doing so.
You find all components related to threading in the c4d.threading module.
The number of threads that should be used can be obtained with GeGetCurrentThreadCount().
A custom thread is based on C4DThread. Such a custom thread can receive, process and return data. Data can be stored as member variables and accessed using custom functions. The Main() function of the thread contains the code that is executed when the thread is running.
from c4d import threading
# input data
data = 
# output data
results = 
# set data
def SetData(self, arguments):
self.data = arguments
# process data
# multiply each item with 2 and store results
for item in self.data:
item = item * 2
# return results
A new thread is created by creating an instance of the thread class. A thread is started using Start(). You can wait for the thread to finish using Wait().
# create thread
thread = MyThread()
# prepare input data
data = 
# set input data
# start thread and wait
# get results
results = thread.GetResults()
If you want to run multiple thread, you have to start these threads an then wait in a loop for all threads to finish (IsRunning()).
Creating a list with items and splitting that into segments is just basic programming.