This viewport overlay displays a user-defined text string in the rendered image. The text string can contain placeholders that reference dynamically computed values from OVITO's data pipeline. This makes it possible to display dynamic information such as the current simulation timestep, number of atoms, or analysis results in a rendered image or movie.
The lower panel displays the list of available attributes which can be referenced in the text and which will be replaced with their current computed values. Note that you can define new attributes using the Python script modifier.