Build Blender as Python Module

Blender is an open source 3d standalone application and it has a feature called scripting. Scripting is a tool that uses the python API to run and control blender. For example, you can create a cube using this script, can apply a texture for that and We can render output using this script as well. This is very useful for the creators to build complex modeling, automate a few steps in their pipeline, and more.

There is another way of using this script, It is “Blender as a Python Module” in external python programs. You may be able to import the blender module as “import bpy” and do the blender-related script in another application. It eliminates the difficulty of running the blender python script from an external file. And we don’t need to run the blender as a software instance in your pc.

The option to build Blender as a Python module is not officially supported, in the sense that Blender.org isn't distributing it along with regular releases. Currently, it's a build option you can enable, for your own use.

This is a build option to be able to import blender into python and access its modules
Here we have some of the possible uses of this module
rendering animations.

• image processing using Blender's compositor.
• video editing (using Blender's sequencer).
• importers, exporters (convert 3D file formats).
• development, accessing bpy from Python IDE's and debugging tools for example.
• automation.

Let’s dive into the initial setup

Building Blender on Windows

Below instructions guide us to building Blender for Windows, with Microsoft Visual Studio.

Install Development Tools

We need to install Subversion, Git, CMake and Visual Studio for windows.

• Install Visual Studio 2019 or 2022 Community Edition (free, be sure to install the 'Desktop Development with C++' workload)
• Install Subversion for Windows (SlikSVN)
• Install Git for Windows In the installer, choose to add Git to your PATH to ensure “make update” can correctly function.
• Install CMake In the installer set the system path option to Add CMake to the system PATH for all users.

Open the command prompt

Then open the command prompt window by hitting the Windows key+R, and then typing cmd.exe

It is important that you use cmd.exe and not powershell or any other shell, the instructions below may not work otherwise.

Download Sources and Libraries

Create a folder to store your copy of the Blender source code. This guide will assume your chosen folder is C:\blender-git.
Download the Blender source code:

cd C:\blender-git
git clone git://git.blender.org/blender.git

Download the Blender libraries:

cd C:\blender-git\blender
make update

make will automatically detect the libraries you need and offer to download them for you. Do note that this set of libraries is several gigabytes large and may take a while to download.
_Need to install Subversion for Windows before run this code. _

Building

Easy (automated) way: see building blender docs for instructions, but run
make bpy

Everything should build as normal except in the cmake directory you will have ./bin/bpy.so (./bin/bpy.pyd on Windows) instead of ./bin/blender

Once this is done successfully, you will have another folder created inside blender-dev that looks something like build_windows_Bpy_x64_vc16_Release depending on you build setup. Now, your folder structure should look like –

C:\blender-git
          |------blender
          |------lib
          |------build_windows_Bpy_x64_vc16_Release

Install

Let’s add the python module to your development environment. This python version should match the python used Blender release. For example, I had Python 3.10 on my pc and I got the latest blender version that was built using Python 3.10. If this doesn't match you may face some compilation error.

1. Create a virtual environment

virtualenv -p python python310
This will create a folder named py37 and install a virtual environment inside that. This is the environment we can use for our projects / addon development. Your folder structure would look like this

C:\blender-dev
          |------blender
          |------lib
          |------build_windows_Bpy_x64_vc16_Release
          |------python310

1. Activate the virtual environment
   .\python310\Scripts\activate.bat

2. Add the following files to the correct location

• copy the file bpy.pyd and all *.dll files from *blender-dev\build_windows_Bpy_x64_vc16_Release\bin\Release* to python310\Lib\site-packages

• Inside *blender-dev\build_windows_Bpy_x64_vc16_Release\bin\Release* folder, you will also see a 3.xx folder depending on what version of Blender you built. In my case, it was 3.14.
  Copy that folder and paste it into the system python directory.
  For example: C:\Users\Jana\AppData\Local\Programs\Python\Python310

Testing

Congratulations!!! Now, you should be good to go.
Open your Command prompt and Run below command to make sure that everything is working fine.

python -c "import bpy; bpy.ops.render.render(write_still=True)"

It will render an image with the cube, you can find the output in C:/tmp/.png