I have exported a simple model (a cube subdivided by 10, then I used smooth vertex).
I export the model, so it can be loaded by my engine (which expects everything to be a quad).
I export it as Wavefront OBJ.
The problem is, Blender sometimes exports faces with 4 vertex indexes (like a quad), sometimes 3 (like a triangle) and sometimes 5 or more (like a polygon, I suppose).
I used Tris to Quads, to make everything a quad, but it didn't work.
I tried exporting all as triangles (Triangulate Faces when exporting), and it does export all in triangles. (I wonder why it, apparently, can't export all as quads).
Well, how do I make Blender export Quads only?
BTW, probably some people will tell me to change the engine to support triangles, but I guess it's too late. Too many things already expect quads. Also, I prefer working with quads, than triangles or polygons.
i fear that this is a dead end for automatical processes. I am not 100% sure though, maybe someone came up with a solution, but i doubt it. Tri to Quad is useful, but as you have experienced, it does not work perfect. If Blender can't change all tris to quads, how could it export them? Well, thats not possible.
Perhaps someone has made an patch or addon which uses better algorithm, but you may need to correct it by hand!
I guess you can use Quads for sure, because regarding graphiccards, they are all converted to tris anyway.
Wish you luck, Gerd