That's probably coz when the model is exported its sharing the vertex at the top.. Would need someone who knows about the modelling program you're using (blender?) to tell you how to address that - in max its something to do with setting up smoothing groups, which effectively ensures that verts have separate normals where needed.
I also recently added an 'separate vertices' option (on the tools menu) that will split all the vertices and duplicate shared ones in the converter (on the Tools menu) .. not sure if that was in 2.13? ( If it isn't, i'll post an update tonight. )
If that option is there, you might be able to resolve things in the converter by separating the vertices then using the Tools -> Recalc Normals option.
Tis great that you're thinking of updating some stuff
I was looking at morvis's firepit model last night thinking that the rocks are neat enough, but the sticks could do with a bit of extra detail..