How to Create a Custom Replicator Function for Changing Camera Position

Omniverse Isaac Sim
1

Hello,

I’m currently experimenting with replicator in Omniverse and would like to randomize the camera position such that it is always on the surface of a sphere with a specified radius.

I have a function that calculates that point:

def get_point_on_hemisphere(radius, azimuth_deg=None, polar_deg=None):
    # azimut is horizontal
    # polar is vertical
    if azimuth_deg is None:
        theta = random.uniform(0, 2 * math.pi)
    else:
        theta = azimuth_deg * (math.pi / 180)

    if polar_deg is None:
        phi = random.uniform(0, 2 * math.pi)
    else:
        phi = azimuth_deg * (math.pi / 180)

    # convert spherical coordinates to cartesian coordinates
    x = radius * math.sin(phi) * math.cos(theta)
    y = radius * math.sin(phi) * math.sin(theta)
    z = radius * math.cos(phi)

    return (x, y, z)

However, when I use this function in the following way, it doesn’t work as expected (I guess this is only called once for the node creation):


def randomize_camera_position_on_hemisphere(camera, look_at, distance, azimut_deg, polar_deg):
    with camera:
        position = utils.get_point_on_hemisphere(radius=distance, azimuth_deg=azimut_deg, polar_deg=polar_deg)
        rep.modify.pose(
            position=position,
            look_at=look_at
        )
    
    return camera.node

with rep.trigger.on_custom_event(event_name=rand_name):
            azimut_deg = random.uniform(0, 360)
            polar_deg = random.uniform(0, 90)
            randomize_camera_position_on_hemisphere(camera=camera, 
                                                    look_at=look_at, 
                                                    distance=distance, 
                                                    azimut_deg=azimut_deg, 
                                                    polar_deg=polar_deg)

Additionally, I tried creating a custom replicator function based on the following post: How to get current frame number in Replicator - Omniverse / Developer - NVIDIA Developer Forums

Unfortunately, I couldn’t get it to work. Is there a new way to create custom replicator functions in Omniverse? If so, could you provide some guidance or examples?

Thank you for your help!

2

Take a look at the docs on registering your own randomizer.