diff --git a/doomsday/client/include/world/bspnode.h b/doomsday/client/include/world/bspnode.h
index ddba2d03bb..097b800b81 100644
--- a/doomsday/client/include/world/bspnode.h
+++ b/doomsday/client/include/world/bspnode.h
@@ -69,6 +69,11 @@ class BspNode : public de::MapElement
      */
     de::Partition const &partition() const;
 
+    /**
+     * Calculates the height of this BSP subtree (note result is not cached).
+     */
+    size_t height() const;
+
     /**
      * Returns @c true iff the specified child is configured.
      */
@@ -91,7 +96,14 @@ class BspNode : public de::MapElement
      *
      * @see hasChild()
      */
-    de::MapElement &child(int left) const;
+    de::MapElement &child(int left);
+    de::MapElement const &child(int left) const;
+
+    inline de::MapElement &right() { return child(Right); }
+    inline de::MapElement const &right() const { return child(Right); }
+
+    inline de::MapElement &left() { return child(Left); }
+    inline de::MapElement const &left() const { return child(Left); }
 
     /**
      * Returns a pointer to the specified child of the BSP node, which may be
@@ -101,7 +113,10 @@ class BspNode : public de::MapElement
      *
      * @see hasChild()
      */
-    inline de::MapElement *childPtr(int left) const {
+    inline de::MapElement *childPtr(int left) {
+        return hasChild(left)? &child(left) : 0;
+    }
+    inline de::MapElement const *childPtr(int left) const {
         return hasChild(left)? &child(left) : 0;
     }
 
diff --git a/doomsday/client/src/world/bspnode.cpp b/doomsday/client/src/world/bspnode.cpp
index d13ff581bf..b8a834116a 100644
--- a/doomsday/client/src/world/bspnode.cpp
+++ b/doomsday/client/src/world/bspnode.cpp
@@ -67,12 +67,24 @@ Partition const &BspNode::partition() const
     return d->partition;
 }
 
+size_t BspNode::height() const
+{
+    DENG2_ASSERT(hasLeft() || hasRight());
+    size_t rHeight = 0;
+    if(hasRight() && right().type() == DMU_BSPNODE)
+        rHeight = right().as<BspNode>().height();
+    size_t lHeight = 0;
+    if(hasLeft() && left().type() == DMU_BSPNODE)
+        lHeight = left().as<BspNode>().height();
+    return (rHeight> lHeight? rHeight : lHeight) + 1;
+}
+
 bool BspNode::hasChild(int left) const
 {
     return *d->childAdr(left) != 0;
 }
 
-MapElement &BspNode::child(int left) const
+MapElement &BspNode::child(int left)
 {
     if(MapElement *childElm = *d->childAdr(left))
     {
@@ -82,6 +94,11 @@ MapElement &BspNode::child(int left) const
     throw MissingChildError("BspNode::child", QString("No %1 child is configured").arg(left? "left" : "right"));
 }
 
+MapElement const &BspNode::child(int left) const
+{
+    return const_cast<MapElement &>(const_cast<BspNode *>(this)->child(left));
+}
+
 void BspNode::setChild(int left, MapElement *newChild)
 {
     if(!newChild || newChild != this)