Getting Started with Scenic

Installation

Scenic requires Python 3.8 or newer. You can install Scenic from PyPI by simply running:

$ pip install scenic

Alternatively, if you want to run some of our example scenarios or modify Scenic, you can download or clone the Scenic repository. Install Poetry, optionally activate the virtual environment in which you would like to run Scenic, and then run:

$ poetry install

If you will be developing Scenic, add the -E dev option when invoking Poetry.

Note

If you are not already using a virtual environment, poetry install will create one. You can then run poetry shell to create a terminal inside the environment for running the commands below.

Note

If you get an error saying that your machine does not have a compatible version, this means that you do not have Python 3.8 or later on your PATH. Install a newer version of Python, either directly from the Python website or using pyenv (e.g. running pyenv install 3.8.5). If you install it somewhere that is not on your PATH (so running python --version doesn’t give you the correct version), you’ll need to run poetry env use /full/path/to/python before running poetry install.

Installing via either pip or Poetry will install all of the dependencies which are required to run Scenic.

Note

For Windows, we recommend using bashonwindows (the Windows subsystem for Linux) on Windows 10. Instructions for installing Poetry on bashonwindows can be found here.

In the past, the shapely package did not install properly on Windows. If you encounter this issue, try installing it manually following the instructions here.

Trying Some Examples

The Scenic repository contains many example scenarios, found in the examples directory. They are organized by the simulator they are written for, e.g. GTA or Webots; there are also cross-platform scenarios written for Scenic’s abstract application domains, e.g. the driving domain. Each simulator has a specialized Scenic interface which requires additional setup (see Supported Simulators); however, for convenience Scenic provides an easy way to visualize scenarios without running a simulator. Simply run scenic, giving a path to a Scenic file:

$ scenic examples/gta/badlyParkedCar2.scenic

This will compile the Scenic program and sample from it, displaying a schematic of the resulting scene. Since this is the badly-parked car example from our GTA case study, you should get something like this:

_images/badlyParkedCar2.png

Here the circled rectangle is the ego car; its view cone extends to the right, where we see another car parked rather poorly at the side of the road (the white lines are curbs). If you close the window, Scenic will sample another scene from the same scenario and display it. This will repeat until you kill the generator (Control-c in Linux; right-clicking on the Dock icon and selecting Quit on OS X).

Scenarios for the other simulators can be viewed in the same way. Here are a few for different simulators:

$ scenic examples/driving/pedestrian.scenic
$ scenic examples/webots/mars/narrowGoal.scenic
$ scenic examples/webots/road/crossing.scenic
_images/pedestrian.png _images/narrowGoal.png _images/crossing.png

The scenic command has options for setting the random seed, running dynamic simulations, printing debugging information, etc.: see Command-Line Options.

Learning More

Depending on what you’d like to do with Scenic, different parts of the documentation may be helpful:

  • If you want to start learning how to write Scenic programs, see the Scenic Tutorial.

  • If you want to learn how to write dynamic scenarios in Scenic, see Dynamic Scenarios.

  • If you want to use Scenic with a simulator, see Supported Simulators (which also describes how to interface Scenic to a new simulator, if the one you want isn’t listed).

  • If you want to add a feature to the language or otherwise need to understand Scenic’s inner workings, see our page on Scenic Internals.