The Best Way to Develop Blender Python Add-ons

When I began developing with Blender Python, I used the text editor that was built in to the Blender GUI. I did this for way too long without realizing how inefficient it was. After talking to a few veteran developers, I learned that the best way to develop Blender Python is outside of Blender.

Background

Most educational resources on Blender Python are fairly introductory, meaning they assume the audience comes from a position of zero experience. When we want to get people interested in Blender Python, we want ease-of-use and minimal setup time. This has led to the championing of Blender’s native text editor. While the text editor is convenient, it is not suitable for large-scale add-on development.

For an in-depth discussion of why the Blender Text Editor is not suitable for large-scale development, see Chapter 7 of my book, The Blender Python API. In this article, we will discuss how to set up common lightweight text editors (Sublime Text, Atom, Notepad++) to develop Blender Python in its own filesystem. This is superior for a multitude of reasons, including portability, dependence safety, and organization.

Where Add-ons Live in Blender

Open your filesystem and navigate to Blender’s installation directory. For Blender 2.78c, the add-on files are found in blender-2.78c/2.78/scripts/addons/, where blender-2.78c is the name of the root directory of the Blender installation. In the addons/ directory, you will find every add-on that is installed on your version of Blender. Some are single scripts, some are flat directories, and some are complex multi-level directories.

To begin developing add-ons directly in Blender’s filesystem, simply open your favorite IDE, and open a project in blender-2.78c/2.78/scripts/addons/ or blender-2.78c/2.78/scripts/addons/my_fresh_new_addon/.

Creating a Loading a Minimal Add-on from the Filesystem

The first script you will need is __init__.py. Go ahead and create this file in your new add-on directory, and paste this into it:

bl_info = {
	"name": "My Add-on Sandbox",
	"author": "Chris Conlan",
	"version": (1, 0, 0),
	"blender": (2, 78, 0),
	"location": "View3D",
	"description": "In-filesystem Add-on Development Sandbox",
	"category": "Development",
}

def register():
	pass

def unregister():
	pass

From there, open Blender and navigate to add-on tab in the user preferences (File -> User Preferences -> Add-ons). Hit “Refresh” or press F8 to have Blender scan the addons/ directory and load all valid add-ons. You should see your new add-on in the Development tab.

The New Workflow

Go ahead and check off the box next to your add-on in the user preferences window. This will load your add-on and notify you of any compile errors in the console.

Excellent! Now we have a workflow. The F8 key refreshes and re-compiles (if necessary) the list of add-ons, and the active add-ons. Now, when you change your add-on in your IDE, save it, swap to Blender, and hit F8 to view your changes. If your add-on fails to compile for any reason, the console will let you know.

Summary

While I love seeing all the cool tutorials out there on the Blender Python API, I do not want developers to feel discouraged by Blender’s text editor. The development process is much easier and cleaner when developing outside the Blender GUI.

The information in this article is important, but not altogether useful for those that are not familiar with the Blender Python API already. I encourage those interested to check out my new book, The Blender Python API for more information.