OmniGraph: Process bundle input

Omniverse General Discussion
1

I want to implement an OmniGraph node in Python. It should get a bundle as an input, this bundle can contain multiple prims.

How can I extract the prims from the bundle input inside the node’s compute(db) function?

Thanks
Bruno

2

Hi @bruno.vetter. Have you taken a look at these two tutorials?

3

Yes, I have. These tutorials do not cover how to work with bundles containing a set of prims. For example, the Ros Publisher Nodes accept a bundle named targetPrims, containing one or more prims. When I try to process such a bundle input inside my compute function, the attributes property returns an empty list. Looking at the OmniGraph docs, there seem to be a concept of having bundles inside bundles, but I am not sure if this is what I am looking for. I haven‘t found any code samples covering this.

4

Thanks Bruno. I’ll reach out to the OmniGraph team for you.

5

Hi! Sincere apologizes for the delay. Here is an example OGN and Python node:

The OgnBundleInputExample.ogn file:

{
    "BundleInputExample": {
        "version": 1,
        "description": "Example node of bundle input",
        "language": "Python",
        "exclude": ["usd", "docs"],
        "categories": "internal:test",
        "uiName": "Example Node: Bundle Input",
        "inputs": {
            "prims": {
                "type": "bundle",
                "description": [ "Input Primitives in Bundle" ]
            }
        },
        "outputs": {
            "count": {
                "type": "int",
                "description": [ "Number of Input Primitives in Bundle" ]
            }
        }
    }
}

The OgnBundleInputExample.py file:

class OgnBundleInputExample:
    @staticmethod
    def compute(db) -> bool:
        input_bundle = db.inputs.prims.bundle
        child_bundles = input_bundle.get_child_bundles()
        db.outputs.count = len(child_bundles)
        return True
6

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