Scenic Install & CARLA Co-Sim On Windows: A Guide

Hey guys! So, you're diving into the awesome world of Scenic and co-simulation with CARLA, that's fantastic! It sounds like you've hit a few bumps in the road, especially when trying to get things running smoothly on Windows. Let's break down the Scenic installation methods and tackle the Windows compatibility question head-on. We'll also explore potential reasons why your co-simulation might not be working as expected and how to troubleshoot it.

Understanding Scenic Installation Methods

When it comes to Scenic installation, there are a couple of primary ways to get it set up on your system. You've correctly identified two common methods: installing from source and using pip directly. Let's explore the nuances of each approach:

Installing from Source

Installing Scenic from source, using the commands you mentioned (cd Scenic followed by python -m pip install -e .), essentially tells pip to install Scenic in "editable" mode. What this means is that instead of copying the Scenic package files into your Python environment's site-packages directory, it creates a symbolic link. This link points directly to the Scenic source code directory on your machine. This method has several advantages. Firstly, it's incredibly useful when you're actively developing or modifying the Scenic library itself. Any changes you make to the source code are immediately reflected when you run your Scenic scripts, without the need to reinstall the package every time. Secondly, it allows you to easily track and manage changes using version control systems like Git. You can create branches, commit changes, and revert to previous versions of the code, giving you greater control over your Scenic environment. Finally, installing from source can be helpful if you need to customize Scenic to fit your specific research or project requirements. You can directly modify the codebase to add new features, fix bugs, or optimize performance.

Installing via pip

On the other hand, directly installing Scenic using pip install scenic===2.1.0b4 fetches the specified version of the package from the Python Package Index (PyPI) and installs it into your Python environment. This is a more straightforward approach for users who simply want to use Scenic without modifying its source code. Pip takes care of downloading the package, resolving dependencies, and placing the necessary files in the correct locations. This method is generally recommended for users who are new to Scenic or who don't need to make any custom changes to the library. It's also a good option for ensuring that you're using a stable and well-tested version of Scenic. However, it's important to note that when you install Scenic using pip, you're essentially working with a snapshot of the code at the time the package was built. If you want to access the latest features or bug fixes, you'll need to update to a newer version of the package.

Key Differences Summarized

In essence, the main difference lies in whether you intend to modify the Scenic source code directly. If you do, installing from source is the way to go. If you just want to use Scenic as a library, pip install is simpler. However, keep in mind that the -e flag in the source installation is crucial for enabling editable mode, allowing your changes to the Scenic code to be immediately reflected without reinstallation.

Windows Compatibility Considerations

Now, let's address the trickier part: Windows compatibility. While Scenic is designed to be platform-independent to a large extent, there can be subtle differences in how it behaves on different operating systems. The core Scenic library, written in Python, should generally work fine on Windows, macOS, and Linux. However, when you start integrating with other tools like CARLA for co-simulation, things can get more complicated. Specifically, some of the underlying dependencies or system-level interactions might behave differently on Windows compared to Ubuntu, which is often the primary development platform for robotics and autonomous driving software.

Potential Windows-Specific Issues

Here are a few potential reasons why you might be encountering issues when trying to co-simulate with CARLA on Windows:

1. Pathing and Environment Variables: Windows uses different path separators (backslash \ instead of forward slash /) and environment variable conventions compared to Linux. This can sometimes cause issues when Scenic or CARLA tries to locate files or libraries. It's crucial to ensure that all paths are correctly specified and that environment variables are set up properly for both Scenic and CARLA on your Windows system.
2. Dependency Conflicts: Certain Python packages or system libraries might have different versions or dependencies on Windows compared to Ubuntu. This can lead to conflicts that prevent Scenic or CARLA from functioning correctly. It's important to carefully manage your Python environment and ensure that all dependencies are compatible with each other.
3. CARLA-Specific Considerations: CARLA itself might have some Windows-specific quirks or limitations. While CARLA is generally well-supported on Windows, certain features or functionalities might not be fully implemented or optimized for the platform. It's worth checking the CARLA documentation and community forums for any known issues or workarounds related to Windows compatibility.
4. File Permissions: Windows file permissions can sometimes be more restrictive than on Linux, which can prevent Scenic or CARLA from accessing or modifying certain files. Make sure that the user account you're using has the necessary permissions to read and write files in the Scenic and CARLA directories.

Debugging Tips for Windows

• Double-check paths: Ensure that all file paths used in your Scenic scripts and CARLA configurations are correctly formatted for Windows (using backslashes as separators).
• Examine environment variables: Verify that all required environment variables (e.g., PYTHONPATH, CARLA_ROOT) are set correctly on your Windows system.
• Isolate dependencies: Create a virtual environment for your Scenic and CARLA projects to isolate dependencies and avoid conflicts with other Python packages.
• Consult the CARLA documentation: Refer to the CARLA documentation for any Windows-specific instructions or troubleshooting tips.

Ubuntu-Specific Code?

Regarding your question about whether there's separate Scenic tool code specifically for Ubuntu, the core Scenic library is designed to be platform-agnostic as possible. However, it's conceivable that some example scripts, utility functions, or integration code might have been initially developed and tested primarily on Ubuntu. This could lead to subtle incompatibilities or assumptions that don't hold true on Windows. If you encounter specific errors or issues when running the code in /safebench/scenario/scenario_data/scenic_data/dynamic_scenario, it's worth examining the code closely to see if there are any platform-specific dependencies or assumptions.

Troubleshooting Steps

1. Inspect the Error Messages: When you run the co-simulation, pay close attention to any error messages or warnings that are displayed. These messages can often provide valuable clues about the root cause of the problem. Look for any indications of pathing issues, dependency conflicts, or other Windows-specific errors.
2. Simplify the Scenario: Try running a simpler Scenic scenario to isolate the issue. If the basic scenario works fine, then the problem might be related to the complexity or specific features of the dynamic_scenario you're trying to run.
3. Step-by-step Debugging: Use a debugger to step through the Scenic code and CARLA integration to see where the execution is failing. This can help you pinpoint the exact line of code that's causing the problem.
4. Search the Scenic and CARLA Forums: Check the Scenic and CARLA community forums for any similar issues that other users might have encountered on Windows. There's a good chance that someone else has already faced the same problem and found a solution.

Conclusion

In conclusion, while Scenic aims for cross-platform compatibility, the reality of co-simulation with tools like CARLA can introduce Windows-specific challenges. By understanding the nuances of installation methods, potential compatibility issues, and employing careful debugging techniques, you'll be well-equipped to get your Scenic simulations running smoothly on Windows. Don't hesitate to dive deep into the error messages, simplify your scenarios, and tap into the collective knowledge of the Scenic and CARLA communities. Happy simulating!