Blender

Blender ships with its own embedded version of Python. Therefore, the simplest (and recommended) way to install COMPAS for Blender is to replace the embedded Python by the Python of a conda environment that already has COMPAS installed.

It is important that the version of Python installed in the conda environment matches the version of Python that was originally shipped with Blender. For Blender 2.83 LTS the version of the bundled Python is 3.7, and for 2.93 LTS it is 3.9.

Installation

These instructions are for the latest Blender 2.93 LTS which ships with Python 3.9 If you don’t have an environment yet with Python 3.9 and COMPAS you can create one with conda.

conda create -n blender -c conda-forge python=3.9 compas --yes

Configuring Blender to use the newly installed environment is slightly different per OS.

Windows

conda activate blender
python -m compas_blender.install -v 2.93

Note that the path %PROGRAMFILES%\\Blender Foundation\\Blender 2.93\\2.93 might be different on your system. Check your Blender installation and change the path accordingly.

OSX

conda activate blender
python -m compas_blender.install /Applications/blender.app/Contents/Resources/2.93

Note that the path /Applications/blender.app/Contents/Resources/2.93 might be different on your system. Check your Blender installation and change the path accordingly.

Linux

conda activate blender
python -m compas_blender.install ~/Blender/2.93

Note that the path ~/Blender/2.93 might be different on your system. Check your Blender installation and change the path accordingly.

On Windows and OSX, if Blender is installed in the default location, you can simply provide the version number.

conda activate blender
python -m compas_blender.install -v 2.93

Verify setup

In Blender, at the interactive Python prompt (>>>) import the following packages

>>> import compas
>>> import compas_blender
>>> import numpy
>>> import scipy

Install Python packages

After replacing the embedded version of Python with the one in the virutual environment, as instructed above, it is not necessary to activate the environment before using Blender. However, when you want to update the installed packages, or add more packages, make sure to activate the Blender environment first. Otherwise, the changes will not have any effect.

conda activate blender
conda install ...

Note

If you want to use blender with a different environment, you simply have to activate that environment and follow the same procedure described above.

Add-ons

For some Blender add-ons, not only the version of Python has to match, but also the version of Numpy. For example, Sverchok, a Grasshopper-type visual programming tool for Blender, will not work with the version of Numpy included in the latest COMPAS releases, even though Blender will.

In those cases, you can simply revert to an earlier version of Numpy that is still compatible with COMPAS in the environment you use with Blender. For Sverchok, this would be version 1.17.5, which is the one shipped with Blender originally. To revert simply do

conda activate blender
conda install numpy=1.17.5

Start Blender

Blender uses the command window of your system to display error messages and other text output. On Windows, the output window can be brought to the front directly from the “Window” menu. On Mac or Linux, you should start Blender from the command line.

By adding the Blender executable to the PATH variable this is really simple. Just add the following to your .bash_profile or .bashrc.

OSX

export PATH="/Applications/blender.app/Contents/MacOS:$PATH"

Linux

export PATH="~/Blender/2.83:$PATH"

Note that this path might be different on your system.

After that starting Blender from the command line is much simpler.

blender

Known Issues

On Windows, Blender sometimes has issues with finding NumPy libraries. If this is the case, the problem can usually be solved by reinstalling NumPy in your environment using pip. However, to avoid issues with other packages that were already installed and depend on a specific version of NumPy, you should install the same version as the one installed originally by conda.

python -c "import numpy; print(numpy.__version__)"

If the above is, for example, 1.20.3

pip install --force-reinstall numpy==1.20.3

Alternatively, you can create a new environment and simply install entire COMPAS using pip.

conda create -n blender python=3.9 cython planarity --yes
conda activate blender
pip install compas
python -m compas_blender.install