Terminology & Concepts

PME Terminology & Concepts

This page explains key terms and concepts used in Blender and PME, aimed at beginners and those seeking deeper understanding.

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Blender Core Concepts

Data (bpy.data)

Provides access to all data stored in a Blender file (.blend). Organized in collections by type like bpy.data.objects and bpy.data.materials. This is a static database where you can access data directly by name or index.

D.objects['Cube']           # Access specific object
D.materials.new("Gold")     # Create new material
D.meshes[0]                 # Access by index

In PME: Use D as shorthand for bpy.data.

Context (bpy.context)

Provides dynamic references based on the user’s current state. Knows about selected objects, active tools, current mode, mouse position, and more. Context changes moment-to-moment based on user actions.

C.active_object            # Currently active object
C.selected_objects         # All selected objects
C.mode                     # Current mode (OBJECT/EDIT/etc.)
C.area.type                # Current area type

In PME: Use C as shorthand for bpy.context.

Data vs Context

• bpy.data: “What exists” - static database of all Blender data
• bpy.context: “What’s happening now” - dynamic state of user interaction

Operators (bpy.ops)

Functional units that execute specific actions in Blender. Everything from adding objects to adjusting bevels is defined as an operator.

• Assignable to hotkeys
• Displayable in menus/buttons
• Callable from Python scripts
• Executable in macros

O.mesh.subdivide()         # Subdivide mesh
O.object.duplicate()       # Duplicate object

In PME: Use O as shorthand for bpy.ops.

Keymap

A collection of hotkey assignments that change based on area type and edit mode.

Example: The G key triggers “Move” in Object Mode, but “Grab” in Sculpt Mode.

PME helps customize these keymaps for your personal workflow.

Properties

Data items in Blender (object positions, material settings, etc.) typically displayed as sliders, checkboxes, and fields in the UI.

With PME you can:

• Display and edit properties in menus/panels
• Reference properties in scripts and Poll functions
• Add custom properties via Property Editor

Mode

Blender’s operational state (Object Mode, Edit Mode, etc.). Each mode has its own set of tools and actions.

PME’s Poll feature allows showing/hiding specific tools based on the active mode.

C.mode == 'EDIT_MESH'      # Check if in Mesh Edit Mode
C.mode == 'SCULPT'         # Check if in Sculpt Mode

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Screen Layout Concepts

Area

A major workspace region in the Blender interface. Different editor types (3D Viewport, Outliner, etc.) each occupy an Area.

Region

Subdivided sections within an Area containing specific UI elements (tools, properties, etc.).

PME’s Panel Group feature can add custom content to regions.

Header

A horizontal bar at the top or bottom of an area, typically containing menus and frequently used tool icons.

Panel

Collapsible groups of UI widgets commonly found in sidebars and properties areas.

With PME you can:

• Create new panels
• Extend existing panels
• Group panels
• Hide unused panels

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PME-Specific Concepts

Menu (in PME context)

A broad term for customizable UI components created in PME:

• Pie Menus
• Regular Menus
• Popup Dialogs
• Macro Operators
• Modal Operators
• And more…

Each menu consists of multiple Slots, each providing different functions.

Slot

An individual element within a menu. Each slot can be configured to:

• Execute commands
• Display or edit properties
• Call submenus
• Draw custom layouts

Command Tab

A tab in the Slot Editor for executing Python code or calling operators directly.

C.active_object.location.x += 1.0

Remember: All code must be on a single line! See Code Examples for details.

Custom Tab

Another tab in the Slot Editor for creating visually-defined UI layouts.

L.box().label(text="Custom Layout")

Poll Method

A Python function that determines whether a menu or tool is currently available. Must return True (available) or False (not available).

# Only show when a mesh object is selected
ao = C.active_object; return ao and ao.type == 'MESH'

Common uses:

• Enable/disable UI elements based on current mode
• Restrict features to specific object types
• Hide invalid tools to prevent errors

Slot Editor

The central UI for defining PME menu/button behavior. Contains multiple tabs:

Tab	Purpose
Command	Execute code
Property	Display properties
Menu	Call other PME menus
Hotkey	Call shortcuts
Custom	Custom layouts

Interactive Panels Mode

A PME mode that displays additional PME tool buttons inside all UI elements, making it easy to:

• Identify menu IDs
• Configure panel extensions
• Customize the UI

Particularly useful when learning PME!

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Advanced Concepts

Macro Operator

Allows executing multiple operators in sequence. PME’s Macro Operator Editor lets you:

• Record operator sequences
• Adjust operator parameters
• Manage execution flow

Great for combining complex workflows into a single click!

Modal Operator

Real-time, interactive operators that respond to continuous user input. PME’s Modal Operator Editor enables:

• Responding to mouse movement
• Key events and state changes
• Real-time feedback and updates

Ideal for building custom interactive tools.

Event System (E)

Blender’s input handling mechanism that tracks keyboard and mouse events.

E.ctrl                     # Is Ctrl pressed?
E.shift                    # Is Shift pressed?
E.type                     # Event type
E.value                    # Event value (PRESS/RELEASE)

In PME: Use E to access the current event.

Layout System (L)

Blender’s system for building UI layouts. PME uses this to:

• Place labels, buttons, and property fields
• Position operators and custom widgets
• Structure UI element hierarchies

L.label(text="Hello")
L.operator("mesh.subdivide")
L.prop(C.scene, "frame_current")

In PME: Use L to access the current layout (in Custom slots).

Operator Execution Context

Determines how an operator executes:

Context	Description
INVOKE_DEFAULT	Interactive mode - waits for user input (mouse position, popup confirmation)
EXEC_DEFAULT	Immediate execution with preset parameters - common in scripts/macros

# Move interactively based on mouse input
O.transform.translate('INVOKE_DEFAULT')
 
# Move immediately by (5, 0, 0) without user input
O.transform.translate('EXEC_DEFAULT', value=(5.0, 0.0, 0.0))

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PME Global Variables Quick Reference

Variable	Equivalent	Description
C	bpy.context	Current context
D	bpy.data	Blender data
O	bpy.ops	Operators
T	bpy.types	Type definitions
P	bpy.props	Property definitions
L	UILayout	Current layout (Custom slot)
E	Event	Current event
U	UserData	Persistent user data storage

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Related Guides

• Getting Started - PME basics
• Code Examples - Scripting patterns
• Hotkey Conflicts - Keymap issues

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External Resources

• Blender Python API
• Context Documentation
• Operators Documentation
• PME Documentation