From BlenderWiki

This is an experimental option to be able to import blender into python and access its modules, importers, exporters rendering, video editing... etc.

This is mainly limited to features which can be usable in background mode, so you cant for instance do OpenGL preview renders.

Building

assuming you have a CMake out-of-source build setup, see: http://wiki.blender.org/index.php/Dev:2.5/Doc/Building_Blender/Linux/Ubuntu/CMake

OSX prerequisites: get Python3.2-Framework from Python.org and install it.

Change these CMake options from the defaults:

WITH_PYTHON_INSTALL=OFF
WITH_PLAYER=OFF
WITH_PYTHON_MODULE=ON

Now build blender normally with 'make install'

Everything should build as normal except in the cmake directory you will have ./bin/bpy.so rather then ./bin/blender

Installation

Linux

To make this available for python copy these files to your site-packages by running

make install

Or if you like to do it manually

cp ./bin/bpy.so /usr/lib/python3.2/site-packages/
cp --recursive ./bin/2.61 /usr/lib/python3.2/site-packages/

Windows

copy bin\bpy.pyd C:\Python32\Lib\site-packages\
copy bin\*.dll C:\Python32\Lib\site-packages\
del C:\Python32\Lib\site-packages\python32.dll
xcopy /E bin\2.61 C:\Python32\

OSX

After compiling and "make install", copy needed files to your python framework

cp ./bin/bpy.so /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/
cp -R ./bin/2.61 /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/

Note. Unlike on *nix C:\Python32\2.57 is not in the site packages, this is because of a difference in how Windows finds the scripts path and should eventually be fixed.

Testing

This allows 'bpy' to be imported from python or other applications/IDE's which embed python, eg:

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

This runs in background mode and has similar restrictions to running a script:

blender --background --python test.py