I understand that in Blender, if you use the the Wavefront .obj export option, that you must select the "Keep Vert Order" button if you wish to maintain vertex order. This can be necessary if you want to correctly work with morph targets. However, if you select this option, no groups (g) or objects (o) are written to the output wavefront .obj file. The only way you really could tell which objects are which in this output is by the ordering of the data or by looking for a new usemtl statement for each object. Why are groups(g)/objects(o) not output if "Keep Vert Order" is selected? What would cause the vertex order to be lost if you don't use the "Keep Vertex Order" (and thus use one of the other options that allows groups(g) or objects(o) to be written)?