Represents the "3DI" entry of the 3d annotation object.

It is an optional entry defined as part of the PDF 1.0 specification.

It contains a bool representing a PDF boolean object.

The PDF specification states that this item assumes a value of true if no value has been provided.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 298, page 512.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 9.33, page 55.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 309, page 640.