diff --git a/doomsday/engine/include/map/surface.h b/doomsday/engine/include/map/surface.h
index e053675843..d4b2a56d66 100644
--- a/doomsday/engine/include/map/surface.h
+++ b/doomsday/engine/include/map/surface.h
@@ -43,7 +43,7 @@ typedef struct surfacedecor_s {
 typedef struct surface_s {
     //runtime_mapdata_header_t header;
     ddmobj_base_t       base;
-    void*               owner;         // Either @c DMU_SIDEDEF, or @c DMU_PLANE
+    de::MapElement     *owner;         // Either @c DMU_SIDEDEF, or @c DMU_PLANE
     int                 flags;         // SUF_ flags
     int                 oldFlags;
     material_t*         material;
diff --git a/doomsday/engine/src/edit_map.cpp b/doomsday/engine/src/edit_map.cpp
index a32539295f..0082d94a89 100644
--- a/doomsday/engine/src/edit_map.cpp
+++ b/doomsday/engine/src/edit_map.cpp
@@ -98,9 +98,9 @@ static SideDef* createSide(void)
     e_map->sideDefs.push_back(side);
 
     side->buildData.index = e_map->sideDefs.size(); // 1-based index, 0 = NIL.
-    side->SW_bottomsurface.owner = (void*) side;
-    side->SW_middlesurface.owner = (void*) side;
-    side->SW_topsurface.owner = (void*) side;
+    side->SW_bottomsurface.owner = side;
+    side->SW_middlesurface.owner = side;
+    side->SW_topsurface.owner = side;
     return side;
 }
 
@@ -1955,7 +1955,7 @@ uint MPE_PlaneCreate(uint sector, coord_t height, const ddstring_t* materialUri,
     Sector* s = e_map->sectors[sector - 1];
 
     Plane* pln = new Plane;
-    pln->surface.owner = (void*) pln;
+    pln->surface.owner = pln;
     pln->height = height;
 
     assignSurfaceMaterial(&pln->surface, materialUri);
diff --git a/doomsday/engine/src/map/bsp/partitioner.cpp b/doomsday/engine/src/map/bsp/partitioner.cpp
index 777ecc5f5e..8604229ac9 100644
--- a/doomsday/engine/src/map/bsp/partitioner.cpp
+++ b/doomsday/engine/src/map/bsp/partitioner.cpp
@@ -371,7 +371,7 @@ struct Partitioner::Instance
             scanRegion.maxX = MAX_OF(line->L_v1origin[VX], line->L_v2origin[VX]) + DIST_EPSILON;
         }
         validCount++;
-        GameMap_LineDefsBoxIterator(map, &scanRegion, testForWindowEffectWorker, (void*)&p);
+        GameMap_LineDefsBoxIterator(map, &scanRegion, testForWindowEffectWorker, &p);
 
         if(p.backOpen && p.frontOpen && line->L_frontsector == p.backOpen)
         {
@@ -1931,11 +1931,13 @@ struct Partitioner::Instance
 
         if(tree.isLeaf())
         {
+            DENG2_ASSERT(dmuOb->type() == DMU_BSPLEAF);
             // There is now one less BspLeaf.
             numLeafs -= 1;
         }
         else
         {
+            DENG2_ASSERT(dmuOb->type() == DMU_BSPNODE);
             // There is now one less BspNode.
             numNodes -= 1;
         }
diff --git a/doomsday/engine/src/map/hedge.cpp b/doomsday/engine/src/map/hedge.cpp
index 8e87f15c08..82d59b8b63 100644
--- a/doomsday/engine/src/map/hedge.cpp
+++ b/doomsday/engine/src/map/hedge.cpp
@@ -422,7 +422,7 @@ int HEdge_GetProperty(const HEdge* hedge, setargs_t* args)
         DMU_GetValue(DMT_HEDGE_LINEDEF, &hedge->lineDef, args, 0);
         break;
     case DMU_FRONT_SECTOR: {
-        Sector* sec = hedge->sector? hedge->sector : NULL;
+        Sector* sec = hedge->sector;
         DMU_GetValue(DMT_HEDGE_SECTOR, &sec, args, 0);
         break; }
     case DMU_BACK_SECTOR: {
diff --git a/doomsday/engine/src/map/p_dmu.cpp b/doomsday/engine/src/map/p_dmu.cpp
index 860cade82a..66fd028e57 100644
--- a/doomsday/engine/src/map/p_dmu.cpp
+++ b/doomsday/engine/src/map/p_dmu.cpp
@@ -1128,18 +1128,18 @@ static int setProperty(void *obj, void *context)
     {
         if(R_UpdateSurface(updateSurface, false))
         {
-            switch(DMU_GetType(updateSurface->owner))
+            switch(updateSurface->owner->type())
             {
             case DMU_SIDEDEF:
-                updateSidedef = (SideDef *)updateSurface->owner;
+                updateSidedef = updateSurface->owner->castTo<SideDef>();
                 break;
 
             case DMU_PLANE:
-                updatePlane = (Plane *)updateSurface->owner;
+                updatePlane = updateSurface->owner->castTo<Plane>();
                 break;
 
             default:
-                LegacyCore_FatalError("SetPropert: Internal error, surface owner unknown.");
+                DENG2_ASSERT(false); // Unsupported type.
             }
         }
     }
diff --git a/doomsday/engine/src/map/r_world.cpp b/doomsday/engine/src/map/r_world.cpp
index 5c5f9dfa79..68e63fa2d6 100644
--- a/doomsday/engine/src/map/r_world.cpp
+++ b/doomsday/engine/src/map/r_world.cpp
@@ -485,7 +485,7 @@ Plane *R_NewPlaneForSector(Sector *sec)
     suf->normal[VZ] = 1;
     V3f_BuildTangents(suf->tangent, suf->bitangent, suf->normal);
 
-    suf->owner = (void*) plane;
+    suf->owner = plane;
     /// @todo The initial material should be the "unknown" material.
     Surface_SetMaterial(suf, NULL);
     Surface_SetMaterialOrigin(suf, 0, 0);
diff --git a/doomsday/engine/src/map/surface.cpp b/doomsday/engine/src/map/surface.cpp
index 3de0871d8e..047dc2b05d 100644
--- a/doomsday/engine/src/map/surface.cpp
+++ b/doomsday/engine/src/map/surface.cpp
@@ -46,9 +46,9 @@ boolean Surface_AttachedToMap(Surface *suf)
 {
     DENG_ASSERT(suf);
     if(!suf->owner) return false;
-    if(DMU_GetType(suf->owner) == DMU_PLANE)
+    if(suf->owner->type() == DMU_PLANE)
     {
-        Sector *sec = ((Plane *)suf->owner)->sector;
+        Sector *sec = suf->owner->castTo<Plane>()->sector;
         if(0 == sec->bspLeafCount)
             return false;
     }
@@ -87,10 +87,10 @@ boolean Surface_SetMaterial(Surface *suf, material_t *mat)
                         R_SurfaceListAdd(GameMap_DecoratedSurfaces(map), suf);
                     }
 
-                    if(DMU_GetType(suf->owner) == DMU_PLANE)
+                    if(suf->owner->type() == DMU_PLANE)
                     {
                         ded_ptcgen_t const *def = App_Materials()->ptcGenDef(*mat);
-                        P_SpawnPlaneParticleGen(def, (Plane *)suf->owner);
+                        P_SpawnPlaneParticleGen(def, suf->owner->castTo<Plane>());
                     }
                 }
             }
@@ -265,10 +265,10 @@ void Surface_UpdateBaseOrigin(Surface *suf)
     LOG_AS("Surface_UpdateBaseOrigin");
 
     if(!suf->owner) return;
-    switch(DMU_GetType(suf->owner))
+    switch(suf->owner->type())
     {
     case DMU_PLANE: {
-        Plane *pln = (Plane *)suf->owner;
+        Plane *pln = suf->owner->castTo<Plane>();
         Sector *sec = pln->sector;
         DENG_ASSERT(sec);
 
@@ -278,7 +278,7 @@ void Surface_UpdateBaseOrigin(Surface *suf)
         break; }
 
     case DMU_SIDEDEF: {
-        SideDef *side = (SideDef *)suf->owner;
+        SideDef *side = suf->owner->castTo<SideDef>();
         LineDef *line = side->line;
         Sector *sec;
         DENG_ASSERT(line);
@@ -327,7 +327,8 @@ void Surface_UpdateBaseOrigin(Surface *suf)
 
     default:
         LOG_DEBUG("Invalid DMU type %s for owner object %p.")
-            << DMU_Str(DMU_GetType(suf->owner)) << de::dintptr(suf->owner);
+            << DMU_Str(suf->owner->type()) << de::dintptr(suf->owner);
+        DENG2_ASSERT(false);
     }
 }
 
diff --git a/doomsday/engine/src/render/lumobj.cpp b/doomsday/engine/src/render/lumobj.cpp
index 147429794a..9b1a1a0968 100644
--- a/doomsday/engine/src/render/lumobj.cpp
+++ b/doomsday/engine/src/render/lumobj.cpp
@@ -951,10 +951,10 @@ END_PROF( PROF_LUMOBJ_FRAME_SORT );
  */
 static boolean createGlowLightForSurface(Surface *suf, void * /*parameters*/)
 {
-    switch(DMU_GetType(suf->owner))
+    switch(suf->owner->type())
     {
     case DMU_PLANE: {
-        Plane *pln = reinterpret_cast<Plane *>(suf->owner);
+        Plane *pln = suf->owner->castTo<Plane>();
         Sector *sec = pln->sector;
 
         // Only produce a light for sectors with open space.
@@ -997,8 +997,7 @@ static boolean createGlowLightForSurface(Surface *suf, void * /*parameters*/)
         return true; // Not yet supported by this algorithm.
 
     default:
-        Con_Error("createGlowLightForSurface: Internal error, unknown type %s.",
-                  DMU_Str(DMU_GetType(suf->owner)));
+        DENG2_ASSERT(false); // Invalid type.
     }
     return true;
 }
diff --git a/doomsday/engine/src/render/rend_decor.cpp b/doomsday/engine/src/render/rend_decor.cpp
index dbaf3f88a0..4ff6e5054c 100644
--- a/doomsday/engine/src/render/rend_decor.cpp
+++ b/doomsday/engine/src/render/rend_decor.cpp
@@ -347,20 +347,20 @@ boolean R_ProjectSurfaceDecorations(Surface *suf, void *context)
     {
         R_ClearSurfaceDecorations(suf);
 
-        switch(DMU_GetType(suf->owner))
+        switch(suf->owner->type())
         {
         case DMU_SIDEDEF: {
-            SideDef *sideDef = (SideDef *)suf->owner;
+            SideDef *sideDef = suf->owner->castTo<SideDef>();
             LineDef *line = sideDef->line;
             updateSideSectionDecorations(line, sideDef == line->L_frontsidedef? FRONT : BACK,
                                          &sideDef->SW_middlesurface == suf? SS_MIDDLE :
                                          &sideDef->SW_bottomsurface == suf? SS_BOTTOM : SS_TOP);
             break; }
         case DMU_PLANE:
-            updatePlaneDecorations((Plane *)suf->owner);
+            updatePlaneDecorations(suf->owner->castTo<Plane>());
             break;
         default:
-            Con_Error("R_ProjectSurfaceDecorations: Internal Error, unknown type %s.", DMU_Str(DMU_GetType(suf->owner)));
+            DENG2_ASSERT(false); // Invalid type.
             break;
         }
         suf->inFlags &= ~SUIF_UPDATE_DECORATIONS;
diff --git a/doomsday/engine/src/server/sv_pool.cpp b/doomsday/engine/src/server/sv_pool.cpp
index 07d397732c..68f887ad02 100644
--- a/doomsday/engine/src/server/sv_pool.cpp
+++ b/doomsday/engine/src/server/sv_pool.cpp
@@ -2318,10 +2318,10 @@ void Sv_NewSoundDelta(int soundId, mobj_t* emitter, Sector* sourceSector,
     else if(sourceSurface)
     {
         type = DT_SECTOR_SOUND;
-        switch(DMU_GetType(sourceSurface->owner))
+        switch(sourceSurface->owner->type())
         {
         case DMU_PLANE: {
-            Plane* pln = (Plane*)sourceSurface->owner;
+            Plane* pln = sourceSurface->owner->castTo<Plane>();
 
             // Clients need to know which emitter to use.
             if(emitter)
@@ -2369,8 +2369,7 @@ void Sv_NewSoundDelta(int soundId, mobj_t* emitter, Sector* sourceSector,
             break; } */
 
         default:
-            DEBUG_Message(("Sv_NewSoundDelta: Invalid DMU type %s for sourceSurface object %p. Sector origin will be used.",
-                           DMU_Str(DMU_GetType(sourceSurface->owner)), sourceSurface->owner));
+            DENG2_ASSERT(false); // Invalid map element type.
             return;
         }
     }
diff --git a/doomsday/libdeng2/src/scriptsys/scriptlex.cpp b/doomsday/libdeng2/src/scriptsys/scriptlex.cpp
index d7bcce0ac3..f548f56966 100644
--- a/doomsday/libdeng2/src/scriptsys/scriptlex.cpp
+++ b/doomsday/libdeng2/src/scriptsys/scriptlex.cpp
@@ -474,7 +474,7 @@ String ScriptLex::unescapeStringToken(Token const &token)
             }
             else if(*ptr == 'x' && (end - ptr > 2))
             {
-                QString num(reinterpret_cast<QChar const *>(ptr + 1), 2);
+                QString num(const_cast<QChar const *>(ptr + 1), 2);
                 duint code = num.toInt(0, 16);
                 c = QChar(code);
                 ptr += 2;