Install compas_cem in only four steps.


We assume you have Anaconda installed in your machine. If not, please download and install it before continuing.

1. Create a virtual environment

First, create a new anaconda environment from the Anaconda Command Prompt if you are on Windows, or from your Terminal if you are on MacOS or Linux.

Here we chose the name of the environment to be cem, but you can call it spacecowboy if you prefer.

conda create -n cem

2. Activate the virtual environment

Next, activate the cem environment. Anaconda environments are like bubbles that keep installations and dependencies isolated from other parts in your machine. In other words, what happens in cem stays in cem! 🕺🏻

conda activate cem

3. Install COMPAS via conda

As a compas extension, compas_cem requires compas to work. The recommended way to install compas is through conda, but you can consult other installation options in the COMPAS installation documentation.

conda install -c conda-forge compas


You may run into errors when installing compas. If you encounter a problem such as not being able to install planarity, that “Microsoft Visual C++ Build Tools are missing”, or that numpy fails to pass a sanity check, please refer to COMPAS known installation issues page for instructions on how to solve these problems.

4. Install COMPAS CEM via pip

Finally, install compas_cem with a one-liner:

pip install compas-cem

To double-check that everything is up and running, type the following in the command line and hit enter:

python -c "import compas_cem"

If no errors show up, celebrate 🎉! You have a working installation of compas_cem.

Install the Grasshopper Plugin

There will be times when modeling a complex structure is easier to do with a few mouse-clicks instead of a hundred lines of code. The Grasshopper (GH) version of compas_cem allows you to use all the important bits of our constrained form-finding engine in a (familiar) visual programming environment.

To additionally install compas_cem as a GH plugin, close Rhino, go to the command line and follow the next three steps:


Make sure that the cem anaconda environment is active and that compas_cem has been installed before proceeding.

1. Remove any leftovers

In case there was an older compas or compas_cem M version linked to Rhino.

python -m compas_rhino.uninstall -v 7.0


The flag -v 7.0 indicates that we will be uninstalling compas_cem and company from Rhino 7. If you are working with Rhino 6, replace that last bit with -v 6.0.

3. Check your Grasshopper installation

Launch grasshopper and start dropping compas_cem components onto the canvas! Send pictures! 🏖


The compas_cem plugin for grasshopper is a collection of .ghuser objects. As such, they have one important limitation: once used in a document, they forget who they are. The don’t know they were created out of a ghuser component, they will be simple GHPython user components. This has an important consequence: if you update compas_cem, those components already in use will NOT be automatically updated.


If you installed compas_cem one day in the past with pip and you want to update it to the latest available version, the update command is the following:

pip install --upgrade compas-cem

Alternatively, if you want to switch to a specific version, type this:

pip install compas-cem==0.16.1


If you update compas_cem and you had installed the grasshopper plugin, the components already in use may no longer work.