Python Operators

This page documents the Python operators and the shared Qt runtime API that Industrial CG Platform adds to Blender.

Blender Operators

wm.blender_vfx_viewlayer_manager_show

Property	Value
Operator ID	wm.blender_vfx_viewlayer_manager_show
Label	ViewLayer Manager
Description	Open or bring to front the ViewLayer Manager window
Category	Window Manager

bpy.ops.wm.blender_vfx_viewlayer_manager_show()

This operator:

1. Enables the blender_vfx_qt_runtime system extension for the current session (if not already enabled).
2. Enables the blender_vfx_viewlayer_manager system extension for the current session (if not already enabled).
3. Opens the ViewLayer Manager Qt window, or brings it to front if already open.

Registration

The operator is registered in:

scripts/startup/bl_operators/blender_vfx_viewlayer_manager.py

The topbar launcher button is added in:

scripts/startup/bl_ui/space_topbar.py

Shared Qt Runtime API

The shared Qt runtime wrapper module at scripts/modules/blender_vfx_qt provides the following public API:

blender_vfx_qt.ensure_runtime()

Ensures the BQt Qt runtime is available for the current session.

from blender_vfx_qt import ensure_runtime

ensure_runtime()  # Enables the runtime extension and imports PySide6

Behavior:

• Enables the blender_vfx_qt_runtime system extension if not already enabled.
• Installs bundled wheels (BQt, PySide6, etc.) into the session's Python path.
• Sets safe-mode environment variables: BQT_DISABLE_WRAP=1, BQT_AUTO_ADD=0, etc.
• Only runs the setup once per session; subsequent calls are no-ops.

blender_vfx_qt.present_window(widget)

Presents a Qt widget by showing it, raising it to the front, and activating its window focus.

from blender_vfx_qt import present_window

# widget is an instantiated QWidget
present_window(my_window_instance)

Parameters:

• widget — A QWidget instance to display.

Behavior:

• Calls .show() on the widget.
• Calls .raise_() on the widget to bring it to the foreground.
• Calls .activateWindow() to grab keyboard and mouse focus.
• Returns the widget instance.

blender_vfx_qt.show_unique_window(cache_ref, factory)

Creates or shows a singleton Qt window, using a caching dictionary and a factory function to ensure only a single instance of the window is active.

from blender_vfx_qt import show_unique_window
from blender_vfx_viewlayer_manager.window import ViewLayerManagerWindow

_window_cache = {"value": None}

def factory():
    window = ViewLayerManagerWindow()
    return window

show_unique_window(_window_cache, factory)

Parameters:

• cache_ref — A dictionary (e.g. {"value": None}) used to store the active window reference.
• factory — A callable (function or lambda) that takes no arguments and returns a newly instantiated QWidget subclass.

Behavior:

• Checks if the cached window exists and is alive (using qt_window_is_alive(widget)).
• If it is alive, calls present_window() on the cached instance to bring it to the foreground.
• If it is not alive (or has been closed/destroyed), invokes the factory function to instantiate a new window, caches the instance in cache_ref["value"], and calls present_window() on the new instance.
• Returns the displayed window instance.

blender_vfx_qt.qt_window_is_alive(widget)

Checks if a Qt widget instance is currently instantiated and has not been garbage-collected or destroyed at the C++ level.

from blender_vfx_qt import qt_window_is_alive

if qt_window_is_alive(my_window):
    print("Window is active and rendering!")

Parameters:

• widget — A QWidget instance (or None).

Behavior:

• Returns False if widget is None.
• Attempts to access the widget's objectName().
• Catches any RuntimeError raised by PySide/PyQt when interacting with a deleted C++ object, returning False if caught.
• Returns True if the widget is alive and healthy.

Bundled Runtime Stack

The Qt runtime is provided by these bundled wheels:

Package	Version	License
bqt	2.2.0	MIT
blender-qt-stylesheet	0.0.3	MIT
QtPy	2.4.3	MIT
packaging	26.2	Apache-2.0 / BSD-2
PySide6	6.11.0	LGPL-3.0
PySide6_Essentials	6.11.0	LGPL-3.0
PySide6_Addons	6.11.0	LGPL-3.0
shiboken6	6.11.0	LGPL-3.0

Source Files

File	Purpose
scripts/startup/bl_operators/blender_vfx_viewlayer_manager.py	Operator registration and bridge logic
scripts/startup/bl_ui/space_topbar.py	Topbar launcher button
scripts/modules/blender_vfx_qt/	Shared Qt runtime wrapper module
release/extensions/system/blender_vfx_qt_runtime/	Runtime extension with bundled wheels
release/extensions/system/blender_vfx_viewlayer_manager/	Manager extension source