Apparently subclassing octree data nodes is confusing, error-prone and can lead to confusing slicing bugs such as #95 and #93 .

In general, deriving custom nodes and octrees should be improved. Options could include better documentation in the code and / or a wiki page, or file templates.

Making ocree nodes virtual (polymorphism) as suggested in #97 is not an option, however, because of the additional memory requirement for the vtable pointers.