В интернете говорят, что если ты хочешь завернуть forward declaration объект unique_ptr то для внешнего класса нужен ДЕСТРУКТОР.
Чо этой падле не нравится?

In file included from /usr/include/c++/4.9/memory:81:0,
                 from meshedobject.hpp:5,
                 from render.cpp:13:
/usr/include/c++/4.9/bits/unique_ptr.h: In instantiation of ‘void std::default_delete<_Tp>::operator()(_Tp*) const [with _Tp = MOImpl]’:
/usr/include/c++/4.9/bits/unique_ptr.h:236:16:   required from ‘std::unique_ptr<_Tp, _Dp>::~unique_ptr() [with _Tp = MOImpl; _Dp = std::default_delete<MOImpl>]’
meshedobject.hpp:20:21:   required from here
/usr/include/c++/4.9/bits/unique_ptr.h:74:22: error: invalid application of ‘sizeof’ to incomplete type ‘MOImpl’
  static_assert(sizeof(_Tp)>0,

#ifndef MESHEDOBJECT_HPP
#define MESHEDOBJECT_HPP

#include <string>
#include <memory>

#include "scene.hpp"
#include "object.hpp"

struct MOImpl;

class MeshedObject: public Object  {
    std::unique_ptr<MOImpl> impl;

    public:
    void render(Scene *scene);
    void init(std::string name, const char *mesh_file, const char *texture_file, const char *vsKey, const char *fsKey);
    void setPosition(float x, float y, float z);

    ~MeshedObject() {}
    // string getName();
};

#endif