Step async problems


I’m trying to run replicator with rep.orchestrator.step_async() and it seems to only be taking the first step before exiting.



import omni.replicator.core as rep
import asyncio;
import time;
from datetime import datetime

async def run_task():

    camera =, 0, 1000))

    sphere_light = rep.create.light(
        temperature=rep.distribution.normal(6500, 500),
        intensity=rep.distribution.normal(35000, 5000),
        position=rep.distribution.uniform((-300, -300, -300), (300, 300, 300)),
        scale=rep.distribution.uniform(50, 100),

    render_product = rep.create.render_product(camera, (1024, 1024))

    torus = rep.create.torus(semantics=[('class', 'torus')] , position=(0, -200 , 100))

    sphere = rep.create.sphere(semantics=[('class', 'sphere')], position=(0, 100, 100))

    cube = rep.create.cube(semantics=[('class', 'cube')],  position=(100, -200 , 100) )

    print("Pre rep.trigger.on_frame()");
    with rep.trigger.on_frame():
        with[torus, sphere, cube]):
                position=rep.distribution.uniform((-100, -100, -100), (200, 200, 200)),
                scale=rep.distribution.uniform(0.1, 2))

    # Initialize and attach writer
    print("Creating the writer");
    writer = rep.WriterRegistry.get("BasicWriter")
    writer.initialize( output_dir="~/_output", rgb=True, bounding_box_2d_tight=True)

    for i in range(10):
        print("pre step {0}".format(i));
        await rep.orchestrator.step_async();
        print("step {0} taken".format(i));
    print("Finished all iterations")
    print("Post rep.orchestrator.stop()");

print("---------------------\nPost ensure_future\n---------------------");

The output I get is

Post ensure_future
2023-01-29 15:17:21 [36,188ms] [Warning] [carb.flatcache.plugin] UsdRelationship /Replicator/SDGPipeline/OgnGroup_02.inputs:prims has multiple targets, which is not supported

Pre rep.trigger.on_frame()
Creating the writer
pre step 0
[38.170s] RTX ready
step 0 taken
pre step 1
[device name]: [path] $ 

and only one set of files appears within ~/_output.

It might be worth mentioning also that this is related to a problem I’ve been having in a larger system where await rep.orchestrator.step_async() simply hangs and doesn’t produce any images at all. I came across this problem while trying to fix that one, and have yet to replicate that problem in a manageable example for a forum.

I also have a similar problem: For loop with orchestrator in Replicator

Can some employee find a solution to this problem?

Hi @glonor and @matthewmunks. I’m checking with the dev team on this.