Represents the "D1" entry of the 3d perpendicular dimension measurement object.

It is a required entry defined as part of the PDF 1.7 Extension Level 3 specification.

It contains an array which contains doubles, representing PDF numeric objects.

For definitive details see:.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 9.39c, page 65.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 328, page 687.