The .r3d file format is an method of storing Inspect3D export settings as XML, ensuring that they are both human- and machine-readable. Inspect3D allows users to save export settings from the Export Results dialog. Previously-saved export settings can also be loaded and used from this dialog.

As an XML document, an .r3d file is made up of hierarchical elements that are demarcated by tags, indicated by the < and > characters. An element consists of a start tag, <elementname>, and end tag, </elementname>, and all of the characters in between. Alternatively, an element can be defined by a single tag, <elementname />.

Tags can also contain attributes in the name=“value” format, further describing the associated element.

1. The top-level element in an .q3d file is settings. It contains an arbitrary (1-n) number of setting elements.

2. The second-, and bottom-, level element in an .r3d file is setting. A setting element has a name attribute (the corresponding setting's name) and a value attribute (the corresponding setting's value).

Formally, an .r3d file respects the Document Type Definition (DTD):

<!DOCTYPE settings [
  <!ELEMENT settings (setting+)>
  <!ATTLIST setting name CDATA #REQUIRED
    setting value CDATA #REQUIRED
  >
]>