‘Background Processing’:

Run blender processes in the background with separate instances of Blender.

Demo of the Background Processor on YouTube

Instructions for Use:

• First, add the background processor as a submodule to your addon module
• Write your own background processing scripts
  • Background processing scripts will be executed from within a separate Blender instance
    • This allows for Blender-only module imports such as bpy and bmesh
    • This also allows for access to the source file’s blend data (if no existing blend data must be accessed, consider setting use_blend_file to False in JobManager.add_job API call for efficiency)
  • Background processing scripts can report their progress with update_job_progress function
    • update_job_progress takes one float argument from 0.0 to 1.0
    • use update_job_progress calls judiciously, as the function has a file write cost
  • Background processing scripts can access the source file’s blend data in two ways
    • Set use_blend_file to True in JobManager.add_job API call (may prove costly for large blend files)
    • Pass blend data directly to the script via the passed_data_blocks parameter of the JobManager.add_job API call
      • Any blend data passed this way will be available as local blend data in the background processing script
      • All blend data passed this way will also be available to the background processing script a passed_data_blocks variable
  • Background processing scripts should include a python_data variable
    • python_data variable should be set to dictionary containing any necessary data to retrieve
    • these data blocks can then be accessed with the JobManager.get_retrieved_python_data API call upon job completion.
  • Background processing scripts should include a data_blocks variable
    • data_blocks variable should be set to list of Blend data blocks
    • The background processor will automatically copy these data blocks to the active instance of Blender upon job completion
    • these data blocks can then be accessed with the JobManager.get_retrieved_data_blocks API call upon job completion.
      • Example use: JobManager.get_retrieved_data_blocks(job).objects
      • NOTE:

          dir(JobManager.get_retrieved_data_blocks(job)) = [
              'actions',
              'armatures',
              'brushes',
              'cache_files',
              'cameras',
              'curves',
              'fonts',
              'grease_pencil',
              'groups',
              'images',
              'ipos',
              'lamps',
              'lattices',
              'linestyles',
              'masks',
              'materials',
              'meshes',
              'metaballs',
              'movieclips',
              'node_groups',
              'objects',
              'paint_curves',
              'palettes',
              'particles',
              'scenes',
              'sounds',
              'speakers',
              'texts',
              'textures',
              'worlds',
          ]

• Send scripts to the JobManager for execution
  • Jobs can be added from within a separate operator/code block using the following code:

      from .job_manager import *  # relative JobManager import path (current path assumes script is in same root folder as 'JobManager.py')
      job = "/tmp/test_script.py"  # REPLACE with path to your background processing script
      job_manager = JobManager.get_instance()
      job_manager.add_job(job)

  • You’ll find the entire background processing API in the Job Manager class (classes/job_manager.py)
  • See classes/add_job.py for an example use of the JobManager class API in a custom operator