Rotation issues with globe anchors that have names matching previously deleted globe anchors

[r-veenstra]

I'm programatically creating multiple globe anchors with child prims. I'm setting the latitude and longitude prim attributes and expecting the globe anchor to position itself on the globe and correctly align with the earths surface.

This works as expected on the first attempt, see image below

However, if I delete these prims and run my script again, the anchors position correctly but are rotated incorrectly

If I rename the prims in my script (eg. append a suffix) the new anchors work fine again. However, if I delete them and run the script again with the same name, it will fail again, so reusing names appears to be an issue.

Tested against the latest globe anchors branch including open-saved-anchors branch

To run my script, use USD Composer and go to window > script editor, paste in the script and hit run

from cesium.omniverse.bindings import acquire_cesium_omniverse_interface

locations = [
    {"name": "NewYork", "latitude": 40.7128, "longitude": -74.0060, "population": 8336817},
    {"name": "LosAngeles", "latitude": 34.0522, "longitude": -118.2437, "population": 39776830},
    {"name": "Chicago", "latitude": 41.8781, "longitude": -87.6298, "population": 2716000},
    {"name": "Houston", "latitude": 29.7604, "longitude": -95.3698, "population": 2320257},
    {"name": "Phoenix", "latitude": 33.4484, "longitude": -112.0740, "population": 1680992},
    {"name": "Philadelphia", "latitude": 39.9526, "longitude": -75.1652, "population": 1584064},
    {"name": "SanAntonio", "latitude": 29.4241, "longitude": -98.4936, "population": 1547253},
    {"name": "SanDiego", "latitude": 32.7157, "longitude": -117.1611, "population": 1423851},
    {"name": "Dallas", "latitude": 32.7767, "longitude": -96.7970, "population": 1343573},
    {"name": "SanJose", "latitude": 37.3541, "longitude": -121.9552, "population": 1030119},
]

ctx = omni.usd.get_context()
stage = ctx.get_stage()

cesium_omniverse_interface = acquire_cesium_omniverse_interface()

for location in locations:

    anchor_path = "/World/" + location["name"] + "_anchor"
    geom_path = anchor_path + "/" + location["name"]

    # Create the anchor prim
    omni.kit.commands.execute(
        "CreateMeshPrimWithDefaultXform", prim_type="Cylinder", prim_path=anchor_path
    )

    # Creat the actual prim geometry - keep object scaling separate from the globe anchor
    omni.kit.commands.execute(
        "CreateMeshPrimWithDefaultXform", prim_type="Cylinder", prim_path=geom_path
    )

    anchor_prim = stage.GetPrimAtPath(anchor_path)
    geom_prim = stage.GetPrimAtPath(geom_path)

    cesium_omniverse_interface.add_global_anchor_to_prim(str(anchor_path))

    anchor_prim.GetAttribute("cesium:anchor:geographicCoordinates").Set(
        (location["latitude"], location["longitude"], 0.0)
    )

    geom_prim = stage.GetPrimAtPath(geom_path)
    geom_prim.GetAttribute("xformOp:scale").Set(
        (50000.0, 1000000.0, 50000.0)
    )

[weegeekps]

Oh, I think I get what is going on here. The Globe Anchors registry is based on path so if you change the paths, such as renaming, things will break. Let me try some things.

[weegeekps]

@r-veenstra How are you deleting the prims?

[weegeekps]

@r-veenstra Okay, so I don't think this is a bug. The issue is our old friend, "USD notification race conditions." If you try the below version of the script where I wait a frame before updating the latitude and location it works. The reason for this is how the notifications work. The create process also creates latitude and longitude update events, which causes a race when you immediately set the latitude and longitude.

In fact, on my machine they never got placed properly in the first case on the first run. Subsequent runs would work... most of the time. There was still a random element based on background usage.

I'm going to close this issue for now but feel free to reopen it if you think there's anything else at work here.

from asyncio import ensure_future
from cesium.omniverse.bindings import acquire_cesium_omniverse_interface

locations = [
    {"name": "NewYork", "latitude": 40.7128, "longitude": -74.0060, "population": 8336817},
    {"name": "LosAngeles", "latitude": 34.0522, "longitude": -118.2437, "population": 39776830},
    {"name": "Chicago", "latitude": 41.8781, "longitude": -87.6298, "population": 2716000},
    {"name": "Houston", "latitude": 29.7604, "longitude": -95.3698, "population": 2320257},
    {"name": "Phoenix", "latitude": 33.4484, "longitude": -112.0740, "population": 1680992},
    {"name": "Philadelphia", "latitude": 39.9526, "longitude": -75.1652, "population": 1584064},
    {"name": "SanAntonio", "latitude": 29.4241, "longitude": -98.4936, "population": 1547253},
    {"name": "SanDiego", "latitude": 32.7157, "longitude": -117.1611, "population": 1423851},
    {"name": "Dallas", "latitude": 32.7767, "longitude": -96.7970, "population": 1343573},
    {"name": "SanJose", "latitude": 37.3541, "longitude": -121.9552, "population": 1030119},
]

ctx = omni.usd.get_context()
stage = ctx.get_stage()

cesium_omniverse_interface = acquire_cesium_omniverse_interface()

async def main():
    for location in locations:

        anchor_path = "/World/" + location["name"] + "_anchor"
        geom_path = anchor_path + "/" + location["name"]

        # Create the anchor prim
        omni.kit.commands.execute(
            "CreateMeshPrimWithDefaultXform", prim_type="Cylinder", prim_path=anchor_path
        )

        # Creat the actual prim geometry - keep object scaling separate from the globe anchor
        omni.kit.commands.execute(
            "CreateMeshPrimWithDefaultXform", prim_type="Cylinder", prim_path=geom_path
        )

        anchor_prim = stage.GetPrimAtPath(anchor_path)
        geom_prim = stage.GetPrimAtPath(geom_path)

        cesium_omniverse_interface.add_global_anchor_to_prim(str(anchor_path))

        for i in range(0, 1):
            await omni.kit.app.get_app().next_update_async()

        anchor_prim.GetAttribute("cesium:anchor:geographicCoordinates").Set(
            (location["latitude"], location["longitude"], 0.0)
        )

        geom_prim = stage.GetPrimAtPath(geom_path)
        geom_prim.GetAttribute("xformOp:scale").Set(
            (50000.0, 1000000.0, 50000.0)
        )

ensure_future(main())

[r-veenstra]

@weegeekps I tried your script, however I'm still seeing the issue. See repro video below.

Screen.sharing.-.2023-10-18.7_00_27.AM.mp4

[weegeekps]

As discussed I think I might have an alternative that might be safer, and we're going to create the first bit of the Cesium Omniverse Python API. I'll be creating a function that allows you to pass in a path, latitude, longitude, and altitude to safely create an anchor on a Prim.

[r-veenstra]

@weegeekps okay, rebuild everything and it looks like my issue was due to running latest code in the globe anchors branch vs actual main (my bad!)

I can confirm now that I 100% always get the race condition as you are experiencing too.