Extract the positions and orientations of specified objects in a Blender scene as JSON

blender_extract_positions.py

# Usage:
# blender my_scene.blend --background --python extract_positions.py -- Foo Bar

import bpy
import json
import sys


def get_object_data(object_names):
    data = {}

    for name in object_names:
        obj = bpy.data.objects.get(name)
        
        if not obj:
            raise Exception(f'Failed to find object "{name}"')

        data[name] = {
            'location': list(obj.location),
            'rotation': [obj.rotation_quaternion.w, obj.rotation_quaternion.x, 
                         obj.rotation_quaternion.y, obj.rotation_quaternion.z]
        }

    return data


def main():
    # The arguments for us come after --
    object_names = sys.argv[sys.argv.index('--') + 1:]
    object_data = get_object_data(object_names)
    print(json.dumps(object_data, indent=4))


if __name__ == '__main__':
    main()