# Error:Prim path expression \['/World/cobotta/onrobot\_rg6\_base\_link'\] is invalid

**URL:** <https://forums.developer.nvidia.com/t/error-prim-path-expression-world-cobotta-onrobot-rg6-base-link-is-invalid/323002>\
**Category:** Isaac Sim\
**Tags:** isaacsim, isaac-sim-v4-5-0\
**Created:** [February 8, 2025, 2:29am UTC](https://forums.developer.nvidia.com/t/error-prim-path-expression-world-cobotta-onrobot-rg6-base-link-is-invalid/323002 "2025-02-08T02:29:53Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![sophia.chen2013](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@sophia.chen2013](https://forums.developer.nvidia.com/u/sophia.chen2013)\
**Post date:** [February 8, 2025, 2:29am UTC](https://forums.developer.nvidia.com/t/error-prim-path-expression-world-cobotta-onrobot-rg6-base-link-is-invalid/323002/1 "2025-02-08T02:29:53Z")

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### Isaac Sim Version

[v] 4.5.0  
 4.2.0  
 4.1.0  
 4.0.0  
 4.5.0  
 2023.1.1  
 2023.1.0-hotfix.1  
 Other (please specify):

### Operating System

[v] Ubuntu 22.04  
 Ubuntu 20.04  
 Windows 11  
 Windows 10  
 Other (please specify):

### GPU Information

NVIDIA GeForce RTX 4070  
NVIDIA-SMI 535.183.01

## Topic Description

### Detailed Description

It have a error when I run the offical tutorial cobotta\_900.  
isaac-sim-4.5.0/standalone\_examples/api/isaacsim.robot.manipulators/cobotta\_900/pick\_up\_example.py

The error is:  
Exception: Prim path expression [‘/World/cobotta/onrobot\_rg6\_base\_link’] is invalid, a prim matching the expression needs to created before wrapping it as view

### Steps to Reproduce

1. 
2. 
3. 

(Add more steps as needed)

### Error Messages

(If applicable, copy and paste any error messages you received)

### Screenshots or Videos

(If applicable, add screenshots or links to videos that demonstrate the issue)

## Additional Information

### What I’ve Tried

(Describe any troubleshooting steps you’ve already taken)

### Related Issues

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### Additional Context

(Add any other context about the problem here)

---

<div class="post-metadata">

**Author:** ![VickNV](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/vicknv/32/14043_2.png) [@VickNV](https://forums.developer.nvidia.com/u/VickNV)\
**Post date:** [February 10, 2025, 9:12pm UTC](https://forums.developer.nvidia.com/t/error-prim-path-expression-world-cobotta-onrobot-rg6-base-link-is-invalid/323002/2 "2025-02-10T21:12:23Z")

</div>

I didn’t encounter the issue by running this command:

```bash
./python.sh standalone_examples/api/isaacsim.robot.manipulators/cobotta_900/pick_up_example.py

```

---

<div class="post-metadata">

**Author:** ![sophia.chen2013](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@sophia.chen2013](https://forums.developer.nvidia.com/u/sophia.chen2013)\
**Post date:** [February 11, 2025, 1:36am UTC](https://forums.developer.nvidia.com/t/error-prim-path-expression-world-cobotta-onrobot-rg6-base-link-is-invalid/323002/3 "2025-02-11T01:36:23Z")

</div>

So how to solve this error please?