Editor Documentation

you can do custom documentation on classes and properties by using .udn files. This is what is used when in the tooltip you see “Hold (Ctrl + Alt) for more”.

Resources

• See FDocumentationModule

When is it displayed ?

As far I saw:

• For Types
  • Displays when you hover a class in the class picker when you create a Blueprint
  • Displays when you hover a class in the component class picker inside an actor.
• For nodes
  • Displays when you hover a node in graph editor.

How to use

(Thanks to Hojo)

1. Get a template from UE_5.X\Engine\Documentation\Source\Shared. For example UE_5.X\Engine\Documentation\Source\Shared\Types\UActorComponent\UActorComponent.INT.udn
2. Use a toll such a VSCode to have a live markdown preview.
3. Put the file in your project/plugin Documentation/Source/XXX folder, if its a type the path is Documentation/Source/Shared/UMyTypeName/UMyTypeName.INT.udn
4. Set the content inside (use the various engine .udn files for examples)

To add images Use ![](MyImage.png), the file must be in a Images folder next to your .udn file.

How it works

The FDocumentationModule has a private var of type IDocumentation which seems to keep track of the SourcePaths as well as the LoadedPages.

See also GetDocumentationLink and GetEnumDocumentationLink in PropertyEditorHelpers.