Blender

Accurate Render Border add-on

Blender add-on allows setting accurate coordinates for render border.

After add-on installation in T-bar additional “ARB” tab appears. On this tab, it’s possible to set accurate values for left-top and right-bottom render border corners coordinates in pixels. Coordinates establish relative to the render size (Properties — Render — Dimensions — Resolution). After pressing the “Set Accurate Render Border” button render border determines in accordance with the entered values.

Add-on is free and open-source. If you want to support it – you can buy the add-on for a convenient price, or set the price to 0 to download it for free.

Creating Blender Add-ons variables with values saved in blend-files

All user-defined classes (panels, operators), registered in Blender API, exists only during Blender runs. After program close they are deleted from memory. Therefore, if some variables are defined in user classes, all of them will be reset after Blender restart.

However, sometimes it is necessary to use in Blender add-on variables with values that not be lost in the process of program restarting. To retain variables values, it needs to wrap them into special class – property, and attach to any object whose properties are stored in * .blend file.

Variables in Blender API operator classes

User defined operator classes, inherited from bpy.types.Operator, are static. Accordingly, only static variables can be defined in them.

Static variable sampleVar definition in SampleClass class:

Creating panels for placing Blender add-ons user interface (UI)

One of the essential conditions of comfortable work is the convenience and speed of accessing add-ons functional. It is not enough to write an add-on and register it in Blender API system. Be sure to give the easy call add-on functions ability to the user. So, any add-on should determine a place to put interface buttons that provide access to its functionality.

This tutorial is for Blender 2.79 and older. For the last Blender versions, please see this tutorial.

All available Blender user interface located on panels. Three panels are the most used: T-bar – opens/hides by pressing the t keyboard button, N-bar – opens/hides by pressing the n button, and the Properties panel – called in the main menu of any window, typed it as Properties.

Blender API allows defining users panels to place add-on functional buttons on any of these three main panels.

Creating Blender add-on

Blender scripting system provides lots of opportunities to simplify and accelerate the workflow, allowing to outsource routine operations to the system and expanding work opportunities through access to the scripting language. However, writing a good script which can be used frequently in various projects, uncomfortable each time to reconnect it to each new project. In addition, this script can be improved with some windows and editable parameters fields. Making complete add-on from the script, you can expand it with additional functionality and connect to the Blender add-ons system.

User-created Blender add-on
User-created Blender add-on