Closed this-username-is-taken closed 3 years ago
Hi @this-username-is-taken list_size_hint
is traditionally only used for face
elements. Without faces, your header looks like it's a point cloud with per-vertex normals. The format is quite generic and face / vertex_index
elements can support any number of vertices per face. e.g. 3 for triangles, 4 for quads, 5+ for n-gons, etc. Triangle strips are another use-case.
Most people stick with either triangles or quads (usually all of the same type, although rarely you'll see mixed tri/quad files). If you assume they're all either tris (list size hint 3) or quads (list size hint 4), then parsing the file into memory is considerably faster. If you generally don't know the format of the files you're importing (e.g. in an engine that can support arbitrary input), it's best to leave this value 0.
Hope that helps!
Does it refer to the number of elements in a list or the size in number of bytes? Or something else?
For example, if I have a file with header like this:
and rows like this:
52.4691 1.49131 82.4518 108 81 62 -0.175547 0.335647 0.925486
Would the list_size_hint be 9 or 27 (6 x 4 + 3 x 1)?