# Build AirSim on Linux & MacOS#

The current recommended and tested environment is Ubuntu 18.04 LTS. Theoretically, you can build on other distros as well, but we haven't tested it.

Only macOS Catalina (10.15) is supported.

We've two options - you can either build inside docker containers or your host machine.

## Host machine#

### Pre-build Setup#

#### Linux - Build Unreal Engine#

• Make sure you are registered with Epic Games. This is required to get source code access for Unreal Engine.

• Clone Unreal in your favorite folder and build it (this may take a while!). Note: We only support Unreal >= 4.24 at present. We recommend using 4.25.

# go to the folder where you clone GitHub projects
git clone -b 4.25 https://github.com/EpicGames/UnrealEngine.git
cd UnrealEngine
./Setup.sh
./GenerateProjectFiles.sh
make

2. Run the Epic Games Launcher, open the Library tab on the left pane. Click on the Add Versions which should show the option to download Unreal 4.25 as shown below. If you have multiple versions of Unreal installed then make sure 4.25 is set to current by clicking down arrow next to the Launch button for the version.

Note: AirSim also works with UE >= 4.24, however, we recommend 4.25. Note: If you have UE 4.16 or older projects, please see the upgrade guide to upgrade your projects.

### Build AirSim#

• Clone AirSim and build it:
# go to the folder where you clone GitHub projects
git clone https://github.com/Microsoft/AirSim.git
cd AirSim

By default AirSim uses clang 8 to build for compatibility with UE 4.25. The setup script will install the right version of cmake, llvm, and eigen.

./setup.sh
./build.sh
# use ./build.sh --debug to build in debug mode

### Build Unreal Environment#

Finally, you will need an Unreal project that hosts the environment for your vehicles. AirSim comes with a built-in "Blocks Environment" which you can use, or you can create your own. Please see setting up Unreal Environment if you'd like to setup your own environment.

## How to Use AirSim#

### Linux#

Once AirSim is setup:

• Go to UnrealEngine installation folder and start Unreal by running ./Engine/Binaries/Linux/UE4Editor.
• When Unreal Engine prompts for opening or creating project, select Browse and choose AirSim/Unreal/Environments/Blocks (or your custom Unreal project).
• Alternatively, the project file can be passed as a commandline argument. For Blocks: ./Engine/Binaries/Linux/UE4Editor <AirSim_path>/Unreal/Environments/Blocks/Blocks.uproject
• If you get prompts to convert project, look for More Options or Convert-In-Place option. If you get prompted to build, choose Yes. If you get prompted to disable AirSim plugin, choose No.
• After Unreal Editor loads, press Play button.

### Mac#

• Browse to AirSim/Unreal/Environments/Blocks.
• Run ./GenerateProjectFiles.sh <UE_PATH> from the terminal, where UE_PATH is the path to the Unreal installation folder. (By default, this is /Users/Shared/Epic\ Games/UE_4.25/) The script creates an XCode workspace by the name Blocks.xcworkspace.
• Open the XCode workspace, and press the Build and run button in the top left.
• After Unreal Editor loads, press Play button.

See Using APIs and settings.json for various options available for AirSim usage.

Tip

Go to 'Edit->Editor Preferences', in the 'Search' box type 'CPU' and ensure that the 'Use Less CPU when in Background' is unchecked.

### [Optional] Setup Remote Control (Multirotor Only)#

A remote control is required if you want to fly manually. See the remote control setup for more details.

Alternatively, you can use APIs for programmatic control or use the so-called Computer Vision mode to move around using the keyboard.

## FAQs#

• I'm getting error <MyProject> could not be compiled. Try rebuilding from source manually.
• This could either happen because of compile error or the fact that your gch files are outdated. Look in to your console window. Do you see something like below?

fatal error: file '/usr/include/linux/version.h''/usr/include/linux/version.h' has been modified since the precompiled header

• If this is the case then look for *.gch file(s) that follows after that message, delete them and try again. Here's relevant thread on Unreal Engine forums.

• If you see other compile errors in console then open up those source files and see if it is due to changes you made. If not, then report it as issue on GitHub.

• Unreal crashed! How do I know what went wrong?

• Go to the MyUnrealProject/Saved/Crashes folder and search for the file MyProject.log within its subdirectories. At the end of this file you will see the stack trace and messages. You can also take a look at the Diagnostics.txt file.
• How do I use an IDE on Linux?

• You can use Qt Creator or CodeLite. Instructions for Qt Creator are available here.
• Can I cross compile for Linux from a Windows machine?

• Yes, you can, but we haven't tested it. You can find the instructions here.
• What compiler and stdlib does AirSim use?

• We use the same compiler that Unreal Engine uses, Clang 8, and stdlib, libc++. AirSim's setup.sh will automatically download them.
• What version of CMake does the AirSim build use?

• 3.10.0 or higher. This is not the default in Ubuntu 16.04 so setup.sh installs it for you. You can check your CMake version using cmake --version. If you have an older version, follow these instructions or see the CMake website.
• Can I compile AirSim in BashOnWindows?

• Yes, however, you can't run Unreal from BashOnWindows. So this is kind of useful to check a Linux compile, but not for an end-to-end run. See the BashOnWindows install guide. Make sure to have the latest version (Windows 10 Creators Edition) as previous versions had various issues. Also, don't invoke bash from Visual Studio Command Prompt, otherwise CMake might find VC++ and try and use that!
• Where can I find more info on running Unreal on Linux?