As I have been working with various render engine AddOns I came up with the concept of the Always On render engine. This is a frame work that can let you code a new Render Engine, if you like, but more importantly you can simply put any code you want in any of the events and it will get executed when Blender generates event. Such as frame change or loading of new BLEND files.
Even though it is a render engine AddOn, there is no need to select it in the render list. More importantly you probably don’t want to. This way you can write code that updates when events are generated and is still compatible with the currently selected render engine.
Nothing amazing here, I just thought I would offer up a working start AddOn for those who are beginning python coding. The always on Render engine approach is kind of like a broad stroke scripting attempt to react to all events when they are generated.
Unzip the attached file into your AddOns folder.
Open up User Preferences and click on the Render category.
Activate Render: Blank and save user preferences.
After activation, the AddOn is always running. There is no need to select it from the drop down list. Examine the console to view the print statements generated by the various events.
Program the UI and events as you see fit. Extend the properties in properties.py to customize for your needs. Put your event code in side events.py. All data/properties are saved with the current Scene.
render_blank.zip (5.86 KB)