diff --git a/doomsday/client/include/world/bspleaf.h b/doomsday/client/include/world/bspleaf.h
index ddfe31c045..01e98a14c2 100644
--- a/doomsday/client/include/world/bspleaf.h
+++ b/doomsday/client/include/world/bspleaf.h
@@ -217,6 +217,32 @@ class BspLeaf : public de::MapElement
      */
     inline Plane &ceiling() const { return plane(Sector::Ceiling); }
 
+    /**
+     * Convenient method of accessing the physical height of the identified sector plane.
+     *
+     * @param planeIndex  Index of the plane to return.
+     *
+     * @see plane(), Plane::height()
+     */
+    inline coord_t planeHeight(int planeIndex) const {
+        return plane(planeIndex).height();
+    }
+
+    /**
+     * Convenient method of accessing the physical height of the sector floor plane.
+     *
+     * @see planeHeight()
+     */
+    inline coord_t floorHeight() const   { return planeHeight(Sector::Floor); }
+
+    /**
+     * Convenient method of accessing the physical height of the sector ceiling plane.
+     *
+     * @see planeHeight()
+     */
+    inline coord_t ceilingHeight() const { return planeHeight(Sector::Ceiling); }
+
+#ifdef __CLIENT__
     /**
      * Returns the identified @em visual sector plane for the BSP leaf (which may
      * or may not be the same as the physical plane). Note that a sector must be
@@ -240,7 +266,6 @@ class BspLeaf : public de::MapElement
      */
     inline Plane &visCeiling() const { return visPlane(Sector::Ceiling); }
 
-#ifdef __CLIENT__
     /**
      * Convenient method of accessing the visual (i.e., smoothed) height of the
      * identified @em visual sector plane.
diff --git a/doomsday/client/src/world/bspleaf.cpp b/doomsday/client/src/world/bspleaf.cpp
index c7fc119ec2..4dfed4d7db 100644
--- a/doomsday/client/src/world/bspleaf.cpp
+++ b/doomsday/client/src/world/bspleaf.cpp
@@ -251,7 +251,7 @@ DENG2_PIMPL(BspLeaf)
 
         geomGroup.biasTracker.clearContributors();
 
-        Plane const &plane     = cluster->plane(planeIndex);
+        Plane const &plane     = cluster->visPlane(planeIndex);
         Surface const &surface = plane.surface();
 
         Vector3d surfacePoint(poly->center(), plane.visHeight());
diff --git a/doomsday/client/src/world/map.cpp b/doomsday/client/src/world/map.cpp
index 3a7cc65fec..4dd08adb98 100644
--- a/doomsday/client/src/world/map.cpp
+++ b/doomsday/client/src/world/map.cpp
@@ -2046,20 +2046,24 @@ void Map::link(mobj_t &mo, byte flags)
     if(mo.dPlayer && mo.dPlayer->mo)
     {
         ddplayer_t *player = mo.dPlayer;
-        Sector &sector = player->mo->bspLeaf->sector();
 
         player->inVoid = true;
-        if(sector.pointInside(player->mo->origin))
+
+        if(player->mo->bspLeaf && player->mo->bspLeaf->hasSector())
         {
+            BspLeaf &bspLeaf = *player->mo->bspLeaf;
+            if(bspLeaf.pointInside(player->mo->origin))
+            {
 #ifdef __CLIENT__
-            if(player->mo->origin[VZ] <  sector.ceiling().visHeight() + 4 &&
-               player->mo->origin[VZ] >= sector.floor().visHeight())
+                if(player->mo->origin[VZ] <  bspLeaf.visCeilingHeight() + 4 &&
+                   player->mo->origin[VZ] >= bspLeaf.visFloorHeight())
 #else
-            if(player->mo->origin[VZ] <  sector.ceiling().height() + 4 &&
-               player->mo->origin[VZ] >= sector.floor().height())
+                if(player->mo->origin[VZ] <  bspLeaf.ceilingHeight() + 4 &&
+                   player->mo->origin[VZ] >= bspLeaf.floorHeight())
 #endif
-            {
-                player->inVoid = false;
+                {
+                    player->inVoid = false;
+                }
             }
         }
     }
diff --git a/doomsday/client/src/world/p_players.cpp b/doomsday/client/src/world/p_players.cpp
index 43e370060d..60741f2ce9 100644
--- a/doomsday/client/src/world/p_players.cpp
+++ b/doomsday/client/src/world/p_players.cpp
@@ -126,34 +126,34 @@ boolean P_IsInVoid(player_t *player)
             return true;
 
         BspLeaf *bspLeaf = ddpl->mo->bspLeaf;
-        if(!bspLeaf->hasSector())
+        if(!bspLeaf->hasSector() || bspLeaf->isDegenerate())
             return true;
 
 #ifdef __CLIENT__
-        if(bspLeaf->ceiling().surface().hasSkyMaskedMaterial())
+        if(bspLeaf->visCeiling().surface().hasSkyMaskedMaterial())
         {
             coord_t const skyCeil = bspLeaf->map().skyFixCeiling();
             if(skyCeil < DDMAXFLOAT && ddpl->mo->origin[VZ] > skyCeil - 4)
                 return true;
         }
-        else if(ddpl->mo->origin[VZ] > bspLeaf->ceiling().visHeight() - 4)
+        else if(ddpl->mo->origin[VZ] > bspLeaf->visCeilingHeight() - 4)
 #else
-        if(ddpl->mo->origin[VZ] > bspLeaf->ceiling().height() - 4)
+        if(ddpl->mo->origin[VZ] > bspLeaf->ceilingHeight() - 4)
 #endif
         {
             return true;
         }
 
 #ifdef __CLIENT__
-        if(bspLeaf->floor().surface().hasSkyMaskedMaterial())
+        if(bspLeaf->visFloor().surface().hasSkyMaskedMaterial())
         {
             coord_t const skyFloor = bspLeaf->map().skyFixFloor();
             if(skyFloor > DDMINFLOAT && ddpl->mo->origin[VZ] < skyFloor + 4)
                 return true;
         }
-        else if(ddpl->mo->origin[VZ] < bspLeaf->floor().visHeight() + 4)
+        else if(ddpl->mo->origin[VZ] < bspLeaf->visFloorHeight() + 4)
 #else
-        if(ddpl->mo->origin[VZ] < bspLeaf->floor().height() + 4)
+        if(ddpl->mo->origin[VZ] < bspLeaf->floorHeight() + 4)
 #endif
         {
             return true;
diff --git a/doomsday/client/src/world/world.cpp b/doomsday/client/src/world/world.cpp
index 228cc0b3a2..1481e865e3 100644
--- a/doomsday/client/src/world/world.cpp
+++ b/doomsday/client/src/world/world.cpp
@@ -589,14 +589,15 @@ DENG2_PIMPL(World)
 
             if(mobj_t *mo = ddpl.mo)
             {
-                if(Sector *sector = map->bspLeafAt(mo->origin).sectorPtr())
+                BspLeaf &bspLeaf = map->bspLeafAt(mo->origin);
+                if(bspLeaf.hasSector() && !bspLeaf.isDegenerate())
                 {
 #ifdef __CLIENT__
-                    if(mo->origin[VZ] >= sector->floor().visHeight() &&
-                       mo->origin[VZ] <  sector->ceiling().visHeight() - 4)
+                    if(mo->origin[VZ] >= bspLeaf.visFloorHeight() &&
+                       mo->origin[VZ] <  bspLeaf.visCeilingHeight() - 4)
 #else
-                    if(mo->origin[VZ] >= sector->floor().height() &&
-                       mo->origin[VZ] <  sector->ceiling().height() - 4)
+                    if(mo->origin[VZ] >= bspLeaf.floorHeight() &&
+                       mo->origin[VZ] <  bspLeaf.ceilingHeight() - 4)
 #endif
                     {
                         ddpl.inVoid = false;