1.2. Install on macOS 10

1.2.1. Install Python 3.9

SimCenter tools require an x86-based version of Python 3.9 to run properly. If you have a different version of Python installed, you will need to add a Python 3.9 x86 version to your system. To see if you have python installed and whether it is compatable with SimCenter tools, issue the following in a terminal window.

import platform

As shown in screenshot below, you should see a Python 3.9 version after issuing the python3 command and the machine=’x86_64’ in the last line of output from the platform.uname() command. If you see another Python version or machine=’arm64’, you will need to install an x86 Python 3.9 on your computer.


Fig. Python: Kernel Version

1. To download a Python installer with your browser open the R2D Download page. There, you will find various files and directories available for download. Locate the file named ‘python-3.9.13-macosx19.9.pkg, which we copied from Python.org. Proceed to download this installer file and then open it on your local machine to initiate the Python installation process.

2. Once you have run the Python.org installer, a popup directory window will appear, displaying several files. Among these, you will find two script files named Update Shell Profile.command.sh and Install CertificateCommand.sh. It’s essential to execute both of these script files to configure Python correctly for terminal use. Simply double-click on each file individually with your mouse to execute them.


Fig. Python: Folder Displayed at Conclusion of Install

3. Once Python is installed, you need to extend it by installing some additional packages. To facilitate this phase of the installation, we created a nheri_simcenter python package that automatically installs all other dependencies. Start a Terminal window and type the following command:

pip3 install nheri_simcenter --upgrade

Make sure you see a message that confirms the successful installation of the nheri-simcenter package before proceeding to the next step.


  1. If you forget to invoke the UpdateShellProfile.command.sh script at the end of the install, you can always execute the correct shell file later to update the PATH variable to point to the Python application.

On Linux systems, the shell is the program that takes commands from the keyboard that you enter in the terminal window and passes them to the operating system to perform by invoking applications and passing data between applications. In the good old days, it was the only interface available to the user, i.e., there was no such thing as Finder! There are a number of shell programs that can be installed and made available to you. The most popular is the bash shell, the up and coming one is the Z shell. Power MacOS users will write shell scripts to do many many useful things. By default the applications that the shell program will invoke are limited to applications in a few specific directories that are defined in the users PATH. Users can modify this path by editing files that the shell program will read from everytime the program is started.

When the frontend application is running the computations it is actually running a backend application using the shell program. As a consequence the shell program must be made aware of the locations of some of the external applications that you have installed as OpenSees and Dakota do not provide installers that automatically do this when they are installed. Other applications, like Tcl provide scripts that you invoke to do it. In short you have to edit the file appropriate to the shell you are using.

To find which shell program you are using when you issue commands inside the terminal window, type the following:

env | grep SHELL

If the result is /bin/bash you will need to edit the .bashrc file or the bash_profile file. If the result is /bin/zsh you will need to edit the .zshrc or .zprofile. Typically, the .bash_profile or the .zprofile file is the one to edit as by design these will invoke the .bashrc or .zshrc file. If in doubt, look for these files in your home directory and see which of these other installers have modified.

  1. Python 3.10 from python.org will also work, though there is no x86 installer. The reason we do not recommend it’s usage is that there is additional settings that need to be modified in the application under the Preferences tab as that python package has a different mechanism for invoking the x86 version, specifically python3-intel64.

1.2.2. Install Java


Java is needed to use OpenSHA to characterize the regional seismic hazard (see Earthquake Scenario Simulation). If you do not plan to use that feature, you can skip this step of the installation.

If you have not yet installed Java, please download the installer from java website. The version 16.0.2 has been tested to be working with the latest R2D app. Follow the on-screen instructions to install Java.


The Java website should automatically detect your operating system and offer the corresponding installer for you to download. Make sure you see “Mac OS X” at the top of the page before downloading the installer.

1.2.4. Download the Application

To download the R2D app, navigate to the R2D Download page which should resemble figDownload-R2D. The download page contains a list of downloadable files and directories.


Fig. R2DTool download page.

Click on the file with a name ending with Mac_Download.dmg to download the R2D app. In the pop-up window, click on the Download button in the bottom right corner. After the download has completed, open the dmg file and copy the R2D app application to a location in your filesystem.


We suggest copying the application to your Desktop. After copying the application, you can move the dmg file to the trash or eject it.

1.2.5. Test the Installation

Once the installation procedure has been completed, it is a good practice to run some basic checks. Navigate to the location where you placed the application and open it by running the R2D.exe executable.


SimCenter apps are code-signed and notarized, but because they are not downloaded from the operating system’s app store, they may not be recognized as safe applications. Depending on your security settings, when you start a SimCenter app for the first time, your operating system may show a dialog box indicating it is unsafe. If this dialog appears, choose the cancel button. Try to start the app again, this time by right clicking on it and selecting open.

If the app still fails to open. You need to go to System Settings->Privacy and Security. Under the Security section you need to at least temprarily select the option to allow applications downloaded from the App Store and Identified Developers. With this schecked try again. If it fails again, go back to System Settings->Privacy and Security. Just below the section you just checked, there should be some text about why the app was stopped and an option to **Open Anayway” , as shown in figure below. Click on the button and the app should start.


Once the application started, you should see the user interface shown in Fig. We recommend running the example problem r2dt-0006 to test the application.


Fig. R2DTool on startup.


When the R2D app is running, open the app/preferences or File/Preferences and make sure that python3 appears under External Applications:Python, as shown in the figure below. If you used older versions of SimCenter tools this was not the default. The exact location of python3 that you installed can be found by opening the terminal application and executing the which python3 command. Enter the path shown as a response to the Preferences panel under Python and then press the Save button.


Set Python Preferences.