Re: [Closed REQ 5826]: "Off" file format question

[daemon]

> What are the primary distinctions between "COFF" and "NOFF" objects?
> Is there a default order in the case of an "OFF" object ...?

Yes -- the order is fixed, and it's the same order for vertices of
all kinds of OOGL objects that allow this sort of thing (OFF, MESH, QUAD).
The codes in the header keyword indicate exactly what kinds of data accompany
each vertex; that's the only indication of what and how much data is there for
each vertex.  (For example, line breaks don't indicate the end of information
about a vertex.)   The convention for data about vertices is mentioned in the
"Vertices" section of "man 5 oogl", also known as the "OOGL File Formats"
section of the Geomview manual.  In particular:

 Vertices
 --------

 Several objects share a common style of representing vertices with
 optional per-vertex surface-normal and color.  All vertices within an
 object have the same format, specified by the header key word.

 All data for a vertex is grouped together (as opposed to e.g. giving
 coordinates for all vertices, then colors for all vertices, and so on).

 The syntax is

 `X  Y  Z'
      (3-D floating-point vertex coordinates) or
 `X  Y  Z  W'
      (4-D floating-point vertex coordinates)

 optionally followed by

 `NX  NY  NZ'
      (normalized 3-D surface-normal if present)

 optionally followed by

 `R  G  B  A'
      (4-component floating-point color if present, each component in range
      0..1.  The A (alpha) component represents opacity: 0 transparent, 1
      opaque.)

 Values are separated by white space, and line breaks
 are immaterial.