# FAQ

> Find answers to common questions about using Wandelbots NOVA with NVIDIA Isaac Sim. Learn about compatible versions, known issues, and solutions for working with the Wandelbots Isaac Sim extension's API.

> **Info:** The FAQ includes all currently known questions arising when using Wandelbots NOVA with NVIDIA Isaac Sim as well as a proposal to resolve the issue. Wandelbots GmbH cannot be held liable for executing these proposals.

### What kind of data is exchanged between NVIDIA Isaac Sim and the NOVA instance?

The Wandelbots NOVA Isaac Sim extension exchanges robot state data, kinematics, trajectories,
robot configuration, instance, cell, motion group and controller data, as well as IO/Bus signals
for peripheral control such as a gluing gun. For the full overview, see
[Data exchange with NVIDIA Isaac Sim](/simulation/data-exchange).

### I cannot connect to NVIDIA Isaac Sim from Robot Pad. What can I do?

1. Ensure that the [Wandelbots NOVA extension is installed and running](/simulation/installation#install-wandelbots-nova-extension).
   If the viewport is not automatically displayed, click on the 3D view icon and select the NVIDIA Omniverse icon.
2. Ensure that you're using the correct port. Usually, the port is detected automatically after authenticating via NVIDIA Isaac Sim.

   Open the Wandelbots NOVA menu in NVIDIA Isaac Sim and open the Isaac Sim Extension API.\
   → A tab in a browser with the Isaac Sim Extension API opens.

   ![Open Omniservice API in your browser.](/assets/nova/omniservice/omniservice-open-api.webp)

   The required port is displayed in the URL after the colon, e.g., `8011`.

   Add the displayed port number to the NVIDIA Isaac Sim instance's IP address, e.g., `http://127.0.0.1:8011`.

   ![Omniservice URL with port number](/assets/nova/omniservice/omniservice-url.webp)

### Where do I get the missing .dll files for NVIDIA Isaac Sim from?

On Windows, missing .dll files in the pytorch tool package cause issues when using Isaac Sim. Here's the workaround:

1. [Download the VS Build Tools](https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2022).
2. During installation, check the checkbox `MSVC v143 - VS 2022 C++ x64/x86 build tools (Latest)` as displayed in the screenshot.

This will add the missing .dll files.

![.dll files required for Isaac Sim](/assets/nova/omniservice/faq-missing-dll-files.webp)

### How do I display an object's coordinate system in NVIDIA Isaac Sim?

Objects visualized in Isaac Sim each have a coordinate system that movements, positions and orientation configurations are referring to.

1. In the stage tab, click on the desired object to display the object's coordinate system.

### Why is the 3D switch option for the viewport not available in Robot Pad?

If the button with the NVIDIA Omniverse icon in Robot Pad that enables switching from the robot visualization to the simulated scene is not available,
NVIDIA Isaac Sim was not started in streaming mode.

In order to change your NVIDIA Isaac Sim instance to streaming you can activate the extension `omni.kit.livestream.webrtc`.

Otherwise check out [how to start NVIDIA Isaac Sim in streaming mode](/simulation/viewport#start-isaac-sim-in-streaming-mode).

### How do I install an older version of the Wandelbots NOVA Isaac Sim Extension (Omniservice)?

To revert to a previous version of the Wandelbots Isaac Sim Extension (Omniservice), use the NVIDIA Isaac Sim extension manager.

1. Use the dropdown menu to select the desired version.\
   Ensure that the selected version is compatible with your NVIDIA IsaacSim and Wandelbots NOVA version.

![Dropdown menu for Wandelbots NOVA extension version in NVIDIA Isaac Sim extension manager.](/assets/nova/omniservice/simulating-revert-version.webp)

### The extension throws an error resolving the module "nova".

If the extension throws an error resolving the module "nova", your NVIDIA Isaac Sim environment has a Python package conflict. To resolve this, please follow these steps:

```
Failed to import python module wandelbots.omni. Error: No module named 'nova.auth.auth_config'.
```

![Delete python packages.](/assets/nova/omniservice/omniservice-failed-to-import-nova.webp)

1. Open the NVIDIA Isaac Sim.
2. Open the Script Editor via "Window" > "Script Editor".
3. Enter the following command in the Script Editor and run it:
   ```python
   import nova
   print(nova.__version__) # this prints the current version of Wandelbots NOVA Python SDK
   print(nova) # this prints the directory where Wandelbots NOVA is installed
   ```
   ![Execute python script in Script Editor.](/assets/nova/omniservice/omniservice-script-editor-get-path-of-pipenv.webp)
4. Check the output of the command and open the directory in your file explorer.
5. Close NVIDIA Isaac Sim
6. Delete all variants of the following folders:
   - `nova`
   - `wandelbots_nova-<version>.dist-info`
   - `.install-cache.json`
   ![Delete python packages.](/assets/nova/omniservice/omniservice-python-packages-02.webp)

   ![Delete python packages.](/assets/nova/omniservice/omniservice-python-packages-01.webp)
7. Now you can restart NVIDIA Isaac Sim and activate the extension with `autoload` enabled.\
   → The terminal next to Isaac Sim installed a version of `wandelbots-nova`.

### How can I include VS Code settings, Python scripts, and modules in the Wandelbots VS Code workspace when exporting a cell?

Currently, VS Code settings, Python scripts, and modules are not included when exporting a cell.

While we implement a user-friendly solution for this, you can copy the data in `~/.config/Code/User` as a temporary workaround for VS Code settings. Similarly, you can manually copy Python scripts and modules to the exported cell's workspace.

### What are some additional resources for learning about NVIDIA Omniverse?

Please check out:

- The [Developer forum](https://forums.developer.nvidia.com/c/omniverse/simulation/69) for the latest on Omniverse/Isaac Sim and enjoy a place to have simple questions answered.

- The [Omniverse discord community](https://discord.com/invite/nvidiaomniverse#:~:text=Official%20Discord%20server%20for%20NVIDIA%20Omniverse,%20the%20computing%20platform%20for) for real-time help and discussions about Omniverse. Also be aware of the welcome rules found [here](https://discord.com/channels/827959428476174346/827959428476174349).

### How do I deal with unsupported dependencies such as a conveyer belt?

Since we removed the conveyer dependency from the extension (version 2.19.0),
as the extension itself does not use any features from the conveyor extension,
you might see the following warning:

`[Warning] [omni.graph.core.plugin] Could not find node type interface for 'isaacsim.asset.gen.conveyor.IsaacConveyor'`

If your scene, for example, depends on a conveyor node in it:

1. Enable the extension `isaacsim.asset.gen.conveyor.ui`.
   → This will also install the base extension `isaacsim.asset.gen.conveyor`.

This will resolve the warning and allow you to use the conveyor belt as before.

### Can I apply NOVA trajectory output directly to an Isaac Sim articulation from Python?

It is possible to use trajectory data generated with the NOVA Python SDK and apply the resulting joint values to a robot articulation in Isaac Sim using Python.
More info can be found [here.](/simulation/introduction)