Application Timers (bpy.app.timers)

Run a Function in x Seconds

import bpy

def in_5_seconds():
    print("Hello World")

bpy.app.timers.register(in_5_seconds, first_interval=5)

Run a Function every x Seconds

import bpy

def every_2_seconds():
    print("Hello World")
    return 2.0

bpy.app.timers.register(every_2_seconds)

Run a Function n times every x seconds

import bpy

counter = 0


def run_10_times():
    global counter
    counter += 1
    print(counter)
    if counter == 10:
        return None
    return 0.1


bpy.app.timers.register(run_10_times)

Assign parameters to functions

import bpy
import functools


def print_message(message):
    print("Message:", message)


bpy.app.timers.register(functools.partial(print_message, "Hello"), first_interval=2.0)
bpy.app.timers.register(functools.partial(print_message, "World"), first_interval=3.0)

Use a Timer to react to events in another thread

You should never modify Blender data at arbitrary points in time in separate threads. However you can use a queue to collect all the actions that should be executed when Blender is in the right state again. Pythons queue.Queue can be used here, because it implements the required locking semantics.

import bpy
import queue

execution_queue = queue.Queue()


# This function can safely be called in another thread.
# The function will be executed when the timer runs the next time.
def run_in_main_thread(function):
    execution_queue.put(function)


def execute_queued_functions():
    while not execution_queue.empty():
        function = execution_queue.get()
        function()
    return 1.0


bpy.app.timers.register(execute_queued_functions)

bpy.app.timers.is_registered(function)

Check if this function is registered as a timer.

Parameters: function (int) – Function to check.
Returns: True when this function is registered, otherwise False.
Return type: bool

bpy.app.timers.register(function, first_interval=0, persistent=False)

Add a new function that will be called after the specified amount of seconds. The function gets no arguments and is expected to return either None or a float. If None is returned, the timer will be unregistered. A returned number specifies the delay until the function is called again. functools.partial can be used to assign some parameters.

Parameters

function (Callable[[], Union[float, None]]) – The function that should called.
first_interval (float) – Seconds until the callback should be called the first time.
persistent (bool) – Don’t remove timer when a new file is loaded.

bpy.app.timers.unregister(function)

Unregister timer.

Parameters: function (function) – Function to unregister.