Editor APIs MVP
In a real-world project, I have counted the occurrence of Editor APIs, and the following 100 APIs are definitely the MVPs in Unreal Python.
TIP
The APIs below starting with unreal.Python...Lib and unreal.ChameleonData are TAPython extension APIs, while the others are UE built-in APIs.
Interaction¶
When writing editor tools, interaction-related APIs are the most commonly used, such as pop-ups, message prompts, logs, notifications, file dialogs, and more.
The numbers before the API indicate the frequency of use, with larger numbers indicating more frequent use.
- 199：unreal.log_warning
Outputs warning information in the console.
- 94: unreal.PythonBPLib.notification
Popup notifications are a user-friendly way of notifying non-developer users.
- 43: unreal.PythonBPLib.get_chameleon_data
Find the corresponding ChameleonData through the tool path to locate the instance of Tool B in Tool A, modify its content, etc.
- 34: unreal.log
- 32: unreal.log_error
Outputs log and error information in the console.
- 28: unreal.PythonBPLib.confirm_dialog
Displays a confirmation dialog.
- 13: unreal.PythonBPLib.open_file_dialog
Opens a file dialog.
- 8: unreal.PythonBPLib.message_dialog
Displays a message dialog.
- 6: unreal.ChameleonData.get_chameleon_window_size
Gets the size of the Chameleon window.
- 4: unreal.PythonBPLib.set_clipboard_content
Sets the content of the clipboard.
- 3: unreal.PythonBPLib.open_directory_dialog
Opens a directory dialog.
- 3: unreal.ChameleonData.set_chameleon_window_size
Sets the size of the Chameleon window.
- 2: unreal.ChameleonData.request_close
Closes the Chameleon window, used in the main tool to close other Chameleon tools, etc.
- 2: unreal.ChameleonData.snapshot_chameleon_window
Captures the content of the Chameleon window interface and saves it as a PNG image.
Assets¶
The following includes asset-related APIs, such as loading assets, getting assets of a specific type, saving assets, deleting assets, importing assets, and more.
- 105: unreal.load_asset
Loads an asset from a path.
- 26: unreal.EditorAssetLibrary.does_asset_exist
Checks if an asset exists.
- 25: unreal.EditorAssetLibrary.save_asset
Saves an asset at a specified path.
- 11: unreal.AssetToolsHelpers.get_asset_tools
Gets Unreal's AssetTools, which perform many asset-related operations, such as create_asset, duplicate_asset, export_assets, and rename_assets.
Gets AssetDatas of a specific type of asset, such as getting all level assets ("World") or all material instances ("MaterialInstance").
- 4: unreal.EditorAssetLibrary.delete_asset
Deletes an asset at a specified location.
- 3: unreal.EditorLoadingAndSavingUtils.save_dirty_packages
Saves all dirty (modified but unsaved) assets.
- 3: unreal.AssetToolsHelpers.get_asset_tools().import_asset_tasks
Sets up an import asset task.
- 3: unreal.PythonBPLib.get_selected_assets_paths
Gets the paths of the currently selected assets.
- 3: unreal.EditorAssetLibrary.duplicate_loaded_asset
Duplicates a loaded asset.
Level/World¶
Level and World are also objects that we often need to operate on in the editor, such as getting the current level, getting the current World, saving the current level, loading levels, and more.
- 24: unreal.EditorLevelLibrary.get_editor_world
Gets the current editor World for UE4.
- 23: unreal.EditorLevelLibrary.set_selected_level_actors
Gets all currently selected Actors.
- 14: unreal.get_editor_subsystem(unreal.UnrealEditorSubsystem).get_editor_world
Gets the current editor World for UE5.
- 11: unreal.EditorLevelLibrary.save_current_level
Saves the current level.
- 10: unreal.EditorLevelLibrary.load_level
Loads a level from a path.
- 9: unreal.EditorLevelLibrary.save_all_dirty_levels
Saves all dirty (modified but unsaved) levels.
- 8: unreal.PythonLevelLib.get_levels
Gets all levels in a specified World.
- 7: unreal.SystemLibrary.get_project_directory
Gets the path of the current project.
- 4: unreal.EditorLevelUtils.add_level_to_world
Adds a level to the current World.
- 4: unreal.EditorLevelLibrary.set_current_level_by_name
Sets the currently active level by name. You can get all levels through get_levels and then activate a specific level using set_current_level_by_name.
Viewport¶
Viewport-related APIs allow us to modify things in the current viewport, such as the camera.
- 10: unreal.PythonBPLib.get_level_viewport_camera_info
Gets the position and rotation of the current scene camera.
- 9: unreal.PythonBPLib.get_viewport_pixels
Gets the pixel content of the current viewport. For example, this API is used when sending viewport content to other tools like stable-diffusion.
- 7: unreal.PythonBPLib.viewport_redraw
Forces a redraw of the current viewport. For example, if we modify the object observed by the camera in the viewport and want to capture the viewport content, we need to ensure that the content in the viewport is updated by calling this viewport_redraw before capturing.
- 4: unreal.PythonBPLib.set_level_viewport_is_in_game_view
Sets the viewport display to 'game mode', equivalent to the shortcut key G in the editor state.
- 4: unreal.PythonBPLib.set_level_viewport_camera_info
Sets the position and rotation of the current scene camera.
Selections¶
The following APIs are related to selections, such as getting the currently selected Actor, getting the currently selected assets, setting the currently selected assets, and so on.
- 13: unreal.PythonBPLib.select_actor
Selects a specific Actor in the editor.
- 9: unreal.PythonBPLib.set_selected_assets_by_paths
Selects assets at a specific path in the Content Browser.
- 6: unreal.PythonBPLib.set_selected_folder_path
Sets the object selected in the World Outliner to a specific Folder. Note that the Folder here refers to the Folder in the Outliner, not the Content Browser.
- 5: unreal.get_editor_subsystem(unreal.EditorActorSubsystem).get_selected_level_actors
Selects a specific Actor in the editor, used in UE5.
- 5: unreal.PythonBPLib.select_none
Deselects all Actors.
- 4: unreal.EditorLevelLibrary.get_selected_level_actors
Selects a specific Actor in the editor, used in UE4.
TIP
Here, we notice that multiple APIs have similar functions, such as: unreal.PythonBPLib.select_actor, unreal.get_editor_subsystem(unreal.EditorActorSubsystem).get_selected_level_actors, unreal.EditorLevelLibrary.get_selected_level_actors are all for selecting specific Actors.
The reason for this is that TAPython started development in the UE4.21 version, and gradually added some APIs that were not in the engine at the time (or I didn't know), and also, as UE5 gradually migrates various EditorLibraries into various Subsystems, it results in duplicate APIs.
Actor/Component¶
APIs related to Actors and Components in the scene.
- 13: unreal.PythonBPLib.get_objects_by_class
Gets all objects of a specific type in the editor.
- 19: unreal.PythonBPLib.spawn_actor_from_class
Creates an Actor from a specific class, such as spawning a unreal.StaticMeshActor during creation.
Gets all Actors in the current editor.
- 10: unreal.PythonPhysicsAssetLib.get_selected_bodies_indexes
Gets the indexes of all bodies in the currently selected physics Asset.
- 10: unreal.PythonBPLib.add_component
Adds a Component to a specific Actor. For example, adding a unreal.StaticMeshComponent to an Actor.
- 8: unreal.PythonBPLib.find_actor_by_name
Gets the Actor with the specified ID Name. Note that this is the ID Name, not the Actor's Label Name.
- 7: unreal.PythonBPLib.spawn_actor_from_object
Creates (copies) a specified Actor into the scene.
- 5: unreal.PythonBPLib.get_selected_components
Gets all currently selected Components.
Query/Modify¶
A large part of UE objects in the editor is accessed and modified using get_editor_property and set_editor_property. Various EditingLibraries also provide operations for modifying resources, objects, etc. In addition to these, TAPython also provides some APIs for getting and setting properties. Of course, if you need more or specific APIs, you can add them yourself.
- 37: unreal.MaterialEditingLibrary.connect_material_expressions
Connects two nodes in a material.
- 22: unreal.MaterialEditingLibrary.create_material_expression
- 17: unreal.MaterialEditingLibrary.create_material_expression_in_function
Adds a material node in a material/material function.
- 15: unreal.MaterialEditingLibrary.set_material_instance_scalar_parameter_value
- 13: unreal.MaterialEditingLibrary.set_material_instance_texture_parameter_value
- 12: unreal.MaterialEditingLibrary.get_texture_parameter_names
Sets/Gets scalar and texture parameters in a material instance.
- 10: unreal.PythonStructLib.add_variable
Adds a variable to a UserDefinedStruct.
- 10: unreal.MaterialEditingLibrary.get_scalar_parameter_names
Gets the names of all Scalar parameters in a material.
- 8: unreal.PythonStructLib.get_variable_names
Gets the names of all variables in a UserDefinedStruct.
- 7: unreal.PythonTextureLib.set_render_target_data
Populates data in a RenderTarget (modifies RenderTarget).
- 6: unreal.PythonDataTableLib.get_row_names
Gets the names of all rows in a DataTable.
- 6: unreal.PythonMaterialLib.set_static_switch_parameters_values
Sets the values in a specified StaticSwitch in a material.
- 5: unreal.MaterialEditingLibrary.get_material_instance_texture_parameter_value
Gets the value of a specified Texture parameter in a material instance.
- 4: unreal.PythonPhysicsAssetLib.get_bodies_from_bone
Gets all bodies on a specified bone in a physics asset.
- 4: unreal.PythonStructLib.remove_variable_by_name
Removes a variable with a specified name from a UserDefinedStruct.
- 4: unreal.PythonStructLib.add_directory_variable
Adds a new dictionary-type variable to a User Defined Struct.
Gets all textures used in a material (does not retrieve textures that exist in the material but are not connected).
- 4: unreal.PythonMaterialLib.get_static_switch_parameter_values
Gets the static switch info of a specified material, including whether it's overridden, etc.
- 4: unreal.PythonDataTableLib.set_property_by_string_at
Sets the content at a specified location in a DataTable.
- 4: unreal.PythonDataTableLib.get_shape
Gets the "row and column" information of a specified DataTable, excluding the title and row names.
- 4: unreal.PythonDataTableLib.get_column_names
Gets the names of all columns in a specified DataTable.
- 4: unreal.MaterialLibrary.set_scalar_parameter_value
Sets the value of a specified Scalar parameter in a material.
- 3: unreal.MaterialEditingLibrary.layout_material_expressions
Automatically lays out nodes in a material.
- 3: unreal.MaterialEditingLibrary.recompile_material
Recompiles a material.
- 3: unreal.PythonPhysicsAssetLib.set_body_rotation
Sets the rotation value of a specified body in a physics asset.
- 3: unreal.PythonStructLib.get_guid_from_property_name
Gets the GUID of a specified variable in a User Defined Struct by PropertyName. This GUID is used in APIs such as unreal.PythonStructLib.rename_variable to specify the variable to be modified.
- 3: unreal.MaterialEditingLibrary.set_material_instance_vector_parameter_value
Sets the value of a specified Vector parameter in a material instance.
- 3: unreal.MaterialLibrary.set_vector_parameter_value
- 3: unreal.MaterialEditingLibrary.get_vector_parameter_names
Gets/Sets the names of all Vector parameters in a material.
- 3: unreal.MaterialEditingLibrary.get_material_instance_scalar_parameter_value
Gets the value of a specified Scalar parameter in a material instance.
- 3: unreal.PythonDataTableLib.add_row
Adds a row to a DataTable.
- 3: unreal.PythonDataTableLib.set_property_by_string
Sets the content at a specified location in a DataTable.
- 3: unreal.PythonEnumLib.get_enum_len
Gets the length of a specified Enum.
- 3: unreal.MaterialEditingLibrary.set_material_instance_parent
Specifies the parent material of a material instance.
- 3: unreal.MathLibrary.make_rot_from_yz
Constructs a Rotator from the Y and Z axes.
- 3: unreal.PythonLandscapeLib.add_adjacent_landscape_proxy
Creates a new LandscapeProxy in the specified direction of a terrain.
Misc¶
Below are some miscellaneous APIs that are very useful when writing editor tools:
- 51: unreal.ScopedSlowTask
Used to add a progress bar for time-consuming tasks.
- 12: unreal.PythonBPLib.exec_python_command
Executes Python commands through a string, and can specify whether these Python commands should be forced to execute in the GameThread in child threads.
- 10: unreal.get_editor_subsystem
Gets the Editor Subsystem. Common SubSystems include: EditorActorSubsystem, AssetEditorSubsystem, LayersSubsystem, UnrealEditorSubsystem, ImportSubsystem, EditorValidatorSubsystem, and more.
- 8: unreal.ScopedEditorTransaction
Used to support Undo and Redo functionality in the editor for subsequent operations.
- 6: unreal.PythonBPLib.execute_console_command
Executes debugging commands in the Cmd through a string.
- 5: unreal.PythonBPLib.gc
Forces UE garbage collection.
- 5: unreal.GuidLibrary.parse_string_to_guid
Converts a string to a Guid format. For example, "A92FC5D4442EF780C79EB49C16F7250E" is converted to a Guid.
- 4: unreal.PythonBPLib.get_all_deps
- 3: unreal.PythonBPLib.get_all_refs
Gets all dependencies and references of a specified object.
- 3: unreal.PythonBPLib.get_modifier_keys_state
Gets the currently pressed modifier keys, such as Shift, Ctrl, Alt, etc.
- 3: unreal.register_slate_post_tick_callback
Registers a Slate Post Tick callback, which will be executed in the Slate's Post Tick.
Reference¶
How to manipulate User Defined ENum, Struct, DataTable with Python in Unreal Engine
Manipulate Material Expression Nodes of Material with Python in Unreal Engine
Modify SImage content and Set Pixels to RenderTarget in Unreal Engine