Hello, I am trying to cut the occipital plane, but I get the crashes and the error message, 

" tksufer.bin:tnl/t_vertex.c:407: update_input_ptrs: Assertion 'a[j].inputstride == vptr-> stride' failed.  Abort(core dumped)"

Anybody did figure it out and fix? Any advice would be most appreciated. 

Hye-Young.