Class Viewer

Tool for examining Unreal Engine classes and creating child classes.

The Class Viewer in Unreal Engine is used to:

  • Examine a hierarchical list of classes that the Editor uses.

  • Create and open Blueprints.

  • Open associated C++ Header files and create new C++ classes based on a specific class.

Opening the Class Viewer

To open the Class Viewer, from Unreal Engine's main menu, go to Tools > Class Viewer.

Class Viewer Interface

Class Viewer window

The Class Viewer interface consists of the following areas:

Number

Name

Description

1

Filters and Search bar

Use the Filters drop-down to restrict the classes that appear to one or more of the following:

  • Actors

  • Placeable Actors

  • Blueprint base classes

Use the Search bar to find classes by name.

2

Settings button

Click this button to open the Settings menu, which you can use to:

  • Expand or collapse all classes.

  • Show or hide internal classes.

  • Show classes from other developers who use the Developer folder.

3

Classes view

Shows all classes that fit the criteria you selected.

Working with Classes

Expanding classes

If a class has children, click the drop-down arrow to the left of the class name (1) to show the children of that class.

Click the drop-down arrow to the right of a class name (2) or right-click the class name to open a context menu with the options below.

The actions you can perform on a class are different based on class type (Blueprint or C++).

Option

Blueprint Class

C++ Class

Create Blueprint

Creates a new Blueprint parented to the selected Blueprint.

Creates a new Blueprint parented to the selected Blueprint.

Edit Blueprint

Opens the selected Blueprint in the Blueprint Editor.

N/A

Find in Content Browser

Finds the Blueprint Actor in the Content Browser.

N/A

Open Source Code

N/A

Opens the class header file in Visual Studio.

Create New C++ Class

N/A

Opens the C++ Class Wizard to create a new class with the selected class as the Parent class.

Dragging and Dropping Classes

Click and drag a Blueprint class from the Class Viewer into the viewport to add a new Blueprint Actor of that class to the currently open Level.

You can also drag any class from the Class Viewer to a combo box in the Details panel or World Settings window, if the class is a child of the class associated with the combo box. For example, you can drag any GameMode child class into the GameMode Override combo box in World Settings.

When dragging classes into a combo box, note that:

  • Classes that haven't been loaded will not appear in the combo box.

  • Dropping a class into the combo box will force-load the class.

Using the Class Picker

You can switch the Class Viewer to Class Picker mode using only code. The Class Picker displays a list of available classes, such as for converting Static Meshes or selecting a parent for a new Blueprint.

Using the Class Picker requires knowledge of how to use C++ in Unreal Engine.

Configuring the Class Picker

FClassViewerInitializationOptions, which is used for initializing a Class Picker, has the following options that control Class Picker behavior:

Option

Description

Mode

This is set to ClassPicker by default.

You can change this to ClassBrowsing, which spawns a normal Class Viewer instead. Note that most of the options below don't work in a Class Viewer.

DisplayMode

You can choose from the following options:

  • TreeView, which shows parent-child relationships between classes.

  • ListView, which shows a simple list of classes.

You can use the following filters to configure which classes show in the Class Picker:

Filter

Description

bIsActorsOnly

Only shows classes that are children of AActor.

bIsPlaceableOnly

Only shows classes that are placeable in the Level. If this is true, bIsActorsOnly will also be assumed to be true.

bIsBlueprintBaseOnly

Only shows Blueprint base classes. This is useful if you only want to see lasses that Blueprints can be created from.

bShowUnloadedBlueprints

Shows unloaded Blueprints, despite their parents being filtered out due to custom filters.

bShowNoneOption

Shows a None option in Class Picker. Doesn't affect Class Viewer. When you pick an item, a NULL class is passed.

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