Ordering of face elements in Wavefront OBJ

Question

I'd like to understand how an OBJ file is structured.

Is there a specific ordering of face elements? Various sources hint that it is usually saved in an order that allows for more straightforward rendering, but no definitive answer. The specification doesn't seem to mention it either. Does it mean that the order is arbitrary and it's up to parsers to deal with it?

Answer 1

I do not know of any such "hint" in the OBJ file format.

I can tell you from experience that they are usually in increasing order of vertex index, which would be good for memory access locality, but again, there's no requirement that this be the case.