# Help with defining Prim Path for new objects in a sceneisaac-sim-api

**URL:** <https://forums.developer.nvidia.com/t/help-with-defining-prim-path-for-new-objects-in-a-sceneisaac-sim-api/301866>\
**Category:** Isaac Sim\
**Created:** [July 31, 2024, 9:47pm UTC](https://forums.developer.nvidia.com/t/help-with-defining-prim-path-for-new-objects-in-a-sceneisaac-sim-api/301866 "2024-07-31T21:47:38Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![stevidunn1](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@stevidunn1](https://forums.developer.nvidia.com/u/stevidunn1)\
**Post date:** [July 31, 2024, 9:47pm UTC](https://forums.developer.nvidia.com/t/help-with-defining-prim-path-for-new-objects-in-a-sceneisaac-sim-api/301866/1 "2024-07-31T21:47:38Z")

</div>

Hello,

I am a new user navigating IsaacLab/Sim. In my project I am trying to change the quadcopter\_env.py exmaple code to have the drone land on a physical cube instead of just hover at the permeable floating cube target location.

I am attempting to insert a new cube at every environment instance at the same location as the target visualization cube to make progress towards the goal of landing.

I am having an issue with defining each env\_id’s cube’s prim path and am getting this error:

```auto
ValueError: A prim already exists at path: '/World/envs/env_0/TargetPhysicalCube'.

```

This is the code I have incorporated to try to do so:

```auto
#create physical target cube in each environment
        for i in range(self.num_envs):
            env_path = f"/World/envs/env_{i}"
            initial_posiiton = (0.0, 0.0, 0.5) #initial pos to be updated later
            create_physical_cube(env_path + "/TargetCube", initial_posiiton)

```

If anyone has any advice on this error or how to go about my task overall it would be much appreciated.