Setup On macOS

These instruction outline how to install Basilisk (BSK) on a clean version of macOS. Basilisk requires the use of Python 3.8.x or greater.

The following python package dependencies are automatically checked and installed in the steps below.

  • pandas numpy matplotlib pytest Pillow conan>=1.40.1, <2.00.0 parse>=1.18.0


If you are running a new Apple computer with the M-series ARM64 processor, be sure to download a version of Python that is compatible with M-series processor. The web site contains Universal binaries for Python 3.9 and onward. Regarding the python packages via pip and brew, the required packages can all be installed readily in a native form using the standard installation instructions below.

Developer Software Tools

In order to run Basilisk on macOS, the following software is necessary:

  1. Get the Apple Xcode Developer tool from the App Store

    • After Xcode is installed, start up the program to let it finish installing development components

    • Open a Terminal window to install the command line tools using:

      $ xcode-select --install
  2. (Optional) Get the SourceTree or GitKraken application to be able to pull and manage a copy of Basilisk

  3. (Optional) Get the PyCharm application to be able to edit python source files

Install Python 3

To install Python 3 on macOS there are two common options:

  1. (Preferred) Download the installer package from This will configure your your macOS environment for Python 3 and can readily be upgraded by downloaded a newer installer package.

  2. Install python 3 through the HomeBrew package management system. The site has the command line to install homebrew from a terminal window using brew install python3.

Install HomeBrew Support Packages

  1. Install HomeBrew using a Terminal window and pasting the install script from the HomeBrew web site.

  2. SWIG version 4.X is compatible with Basilisk. Install the SWIG software package using:

    $ brew install swig
  3. If you want to install the HomeBrew version of cmake, you can do so with:

    $ brew install cmake
    $ brew link cmake

Setting up the Python Environment


The following instructions recommend installing all the required python packages either in a virtual environment or in the user ~/Library/Python folder. This has the benefit that no sudo command is required to install and run Basilisk, and the user Python folder can readily be replaced if needed. If you are familiar with python you can install in other locations as well.


If you wish to use the HomeBrew version of python, or generally have multiple copies of python installed on your system, configure the CMake Python paths as described in Using a Custom Python Installation after following these instructions.


We suggest you remove any other python packages (such as Anaconda), or change the path in your terminal shell if you really want to keep it.

In the following instructions, be sure to follow the sequence of tasks as outlined below.

Using A Python Virtual Environment


We strongly recommend using a python virtual environment while installing basilisk or running basilisk modules. For more info, read this. The virtual environment has the benefit that you won’t have conflicts with other versions of Python or python packages that your computer has installed. It lets you install packages specific to this environment and they won’t interfere with other python projects you may have. However, you must turn this environment on and off each time you want to use it.

The following steps show how to create, active ad de-activate a virtual environment. The remaining installation steps work regardless if done within a virtual environment or not.

  • In a Terminal window change your current directory to be the Basilisk folder, then create a virtual environment using:

    $ python3 -m venv .venv

    This creates a hidden folder inside the Basilisk folder which will store all the python packages and environment information.

  • Activate virtual environment when needing configure, build or run Basilisk:

    $ source .venv/bin/activate

    The above step will add (.venv) before the prompt.

  • Deactivate the virtual environment to return to the normal operating system environment:

    (.venv) $ deactivate

Installing required python support packages

  • Basilisk uses conan for package managing. In order to do so, users must ensure wheel is installed and install conan:

    (.venv) $ pip3 install wheel 'conan<2.0'

    The conan repositories information is automatically setup by


    If you are upgrading from a version of Basilisk prior to 1.8.0, be sure to delete the .conan folder in your home directory to create a clean copy compatible with the current build system.

  • The following python packages are the minimum required packages for Basilisk. They are installed and checked for the correction version in the steps below.

    • pandas numpy matplotlib pytest Pillow conan>=1.40.1, <2.00.0 parse>=1.18.0

  • Optional Packages: The above directions install the Basilisk base software. There are a series of optional packages that enhance this capability, including pytest to run an automated test suite of unit and integrated tests.

Build Project Process via Terminal

When all the prerequisite installations are complete, the project can be built as follows.

  1. The will setup, configure and run the Basilisk build. For a basic installation, from the root Basilisk folder use:

    (.venv) $ python3

    For other configure and build options, see Building the Software Framework. This creates the Xcode project in dist3.


    Note that the default configuration is building for Release. When you open the project in XCode, note that you need to build for profiling. Otherwise you get errors about not being able to find appropriate conan installed libraries.

    The python3 process will verify that the minimum required Basilisk python packages are installed, and that the version is correct. If not, the user is prompted to install the package with pip3 in the system or user folder.


    If you wish to use the another version of python 3 configure the Python paths in Using a Custom Python Installation


    If you get an error message in cmake saying it can’t find the compiler tools, open a Terminal window and type:

    $ xcode-select -p

    This should return:


    If instead you get a different director such as /Library/Developer/CommandLineTools, then correct this compiler directory path using:

    sudo xcode-select --reset

    Now clear the Cmake cache and try running the configure and build process again.

  2. To test your setup you can run one of the Integrated Example Scripts:

    • For example, in the terminal window, make basilisk/examples/ the current directory.

    • Run one of the tutorial scenarios, such as:

      (.venv) $ python3

Building with IDE

Conan file will build the project by default. However, this can take longer to compile than building the Basilisk project in Xcode directly. Further, if you are developing for Basilisk you often just want to configure the Basilisk Xcode project file and not build right away. To change the default behavior disable the automatic build using:

  1. Set the buildProject argument to False using:

    (venv) $ python3 --buildProject False
  2. Open the Xcode project file inside dist3. This is basilisk.xcodeproj on macOS.

    • The source code should appear and be ready for use

    • Ensure that the target scheme is set to ALL_BUILD as shown in figure above

    • Within Xcode now go under Product/Build For/Profiling to build for Release.


  1. Q: Experiencing problems when trying to change the directory in which to clone the url

    • A: clone it in the default directory, and copy it into the preferred one after it is done cloning.

  2. Q : Permission denied when using brew

    • A: Add sudo to the start of the command. If you do not have superuser access, get superuser access.

  3. Q : I updated my macOS system to the latest released, and I can no longer run CMake or build with Xcode.