There are several mechanisms for displaying messages and notifications to the user. You can use the following methods and macros to display text messages:

• Interface::HUDMessageShow() – Displays a message as text overlay, which is also called the head's up display (HUD) in 3d view. You can hide the HUD with Interface::HUDMessageHide().
• Interface::SetStatus() – Displays a message in the status bar.
• Interface::MessageBox() – Displays a modal dialog box to the user.
• MB_ERROR – A macro that creates an Error object and displays an error message.

The following are non-textual notification mechanisms to indicate the progress of a long running operation:

• Interface::WaitCursorStart() – Shows a wait cursor. The cursor can be restored using Interface::WaitCursorEnd().
• Interface::ProgressStart() – Displays a progress bar.
• Interface::ProgressSet() – Updates the current progress bar.
• Interface::ProgressAdd() – Updates the current progress bar by adding one to the progress value.
• Interface::ProgressEnd() – Removes the current progress bar whether or not the process is complete.