diff --git a/src/DotRecast.Recast/RcHeightfield.cs b/src/DotRecast.Recast/RcHeightfield.cs
index dd8b5fc..b46cc99 100644
--- a/src/DotRecast.Recast/RcHeightfield.cs
+++ b/src/DotRecast.Recast/RcHeightfield.cs
@@ -22,29 +22,17 @@ using DotRecast.Core.Numerics;
 
 namespace DotRecast.Recast
 {
-    /** Represents a heightfield layer within a layer set. */
+    /// A dynamic heightfield representing obstructed space.
+    /// @ingroup recast
     public class RcHeightfield
     {
-        /** The width of the heightfield. (Along the x-axis in cell units.) */
-        public readonly int width;
-
-        /** The height of the heightfield. (Along the z-axis in cell units.) */
-        public readonly int height;
-
-        /** The minimum bounds in world space. [(x, y, z)] */
-        public readonly RcVec3f bmin;
-
-        /** The maximum bounds in world space. [(x, y, z)] */
-        public RcVec3f bmax;
-
-        /** The size of each cell. (On the xz-plane.) */
-        public readonly float cs;
-
-        /** The height of each cell. (The minimum increment along the y-axis.) */
-        public readonly float ch;
-
-        /** Heightfield of spans (width*height). */
-        public readonly RcSpan[] spans;
+        public readonly int width; //< The width of the heightfield. (Along the x-axis in cell units.)
+        public readonly int height; //< The height of the heightfield. (Along the z-axis in cell units.)
+        public readonly RcVec3f bmin; //< The minimum bounds in world space. [(x, y, z)]
+        public RcVec3f bmax; //< The maximum bounds in world space. [(x, y, z)]
+        public readonly float cs; //< The size of each cell. (On the xz-plane.)
+        public readonly float ch; //< The height of each cell. (The minimum increment along the y-axis.)
+        public readonly RcSpan[] spans; //< Heightfield of spans (width*height).
 
         /** Border size in cell units */
         public readonly int borderSize;
diff --git a/src/DotRecast.Recast/RcSpanPool.cs b/src/DotRecast.Recast/RcSpanPool.cs
new file mode 100644
index 0000000..393ceea
--- /dev/null
+++ b/src/DotRecast.Recast/RcSpanPool.cs
@@ -0,0 +1,38 @@
+/*
+Copyright (c) 2009-2010 Mikko Mononen memon@inside.org
+DotRecast Copyright (c) 2023 Choi Ikpil ikpil@naver.com
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+namespace DotRecast.Recast
+{
+    /// A memory pool used for quick allocation of spans within a heightfield.
+    /// @see rcHeightfield
+    public class RcSpanPool
+    {
+        public RcSpanPool next; //< The next span pool.
+        public readonly RcSpan[] items; //< Array of spans in the pool.
+
+        public RcSpanPool()
+        {
+            items = new RcSpan[RcConstants.RC_SPANS_PER_POOL];
+            for (int i = 0; i < items.Length; ++i)
+            {
+                items[i] = new RcSpan();
+            }
+        }
+    }
+}
\ No newline at end of file