diff --git a/src/DotRecast.Detour/DtBVNode.cs b/src/DotRecast.Detour/DtBVNode.cs
index 2de5e75..8170277 100644
--- a/src/DotRecast.Detour/DtBVNode.cs
+++ b/src/DotRecast.Detour/DtBVNode.cs
@@ -18,6 +18,8 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
+
 namespace DotRecast.Detour
 {
     /**
@@ -26,6 +28,7 @@ namespace DotRecast.Detour
  * @note This structure is rarely if ever used by the end user.
  * @see MeshTile
  */
+    [Serializable]
     public class DtBVNode
     {
         /** Minimum bounds of the node's AABB. [(x, y, z)] */
diff --git a/src/DotRecast.Detour/DtMeshData.cs b/src/DotRecast.Detour/DtMeshData.cs
index c2ad019..73c71f4 100644
--- a/src/DotRecast.Detour/DtMeshData.cs
+++ b/src/DotRecast.Detour/DtMeshData.cs
@@ -18,8 +18,11 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
+
 namespace DotRecast.Detour
 {
+    [Serializable]
     public class DtMeshData
     {
         /** The tile header. */
diff --git a/src/DotRecast.Detour/DtMeshHeader.cs b/src/DotRecast.Detour/DtMeshHeader.cs
index de3d6a5..a79b9e4 100644
--- a/src/DotRecast.Detour/DtMeshHeader.cs
+++ b/src/DotRecast.Detour/DtMeshHeader.cs
@@ -18,11 +18,13 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
 using DotRecast.Core.Numerics;
 
 namespace DotRecast.Detour
 {
     /** Provides high level information related to a dtMeshTile object. */
+    [Serializable]
     public class DtMeshHeader
     {
         /** Tile magic number. (Used to identify the data format.) */
diff --git a/src/DotRecast.Detour/DtNavMeshParams.cs b/src/DotRecast.Detour/DtNavMeshParams.cs
index 81cf963..5f0168d 100644
--- a/src/DotRecast.Detour/DtNavMeshParams.cs
+++ b/src/DotRecast.Detour/DtNavMeshParams.cs
@@ -18,6 +18,7 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
 using DotRecast.Core.Numerics;
 
 namespace DotRecast.Detour
diff --git a/src/DotRecast.Detour/DtOffMeshConnection.cs b/src/DotRecast.Detour/DtOffMeshConnection.cs
index 244f005..5d6cf63 100644
--- a/src/DotRecast.Detour/DtOffMeshConnection.cs
+++ b/src/DotRecast.Detour/DtOffMeshConnection.cs
@@ -18,12 +18,14 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
 using DotRecast.Core.Numerics;
 
 namespace DotRecast.Detour
 {
     /// Defines an navigation mesh off-mesh connection within a dtMeshTile object.
     /// An off-mesh connection is a user defined traversable connection made up to two vertices.
+    [Serializable]
     public class DtOffMeshConnection
     {
         /// The endpoints of the connection. [(ax, ay, az, bx, by, bz)]
diff --git a/src/DotRecast.Detour/DtPoly.cs b/src/DotRecast.Detour/DtPoly.cs
index 0ef2a77..37f0c6a 100644
--- a/src/DotRecast.Detour/DtPoly.cs
+++ b/src/DotRecast.Detour/DtPoly.cs
@@ -18,18 +18,21 @@ freely, subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
+using System;
+
 namespace DotRecast.Detour
 {
     /** Defines a polygon within a MeshTile object. */
+    [Serializable]
     public class DtPoly
     {
-        public readonly int index;
+        public int index;
 
         /** The indices of the polygon's vertices. The actual vertices are located in MeshTile::verts. */
-        public readonly int[] verts;
+        public int[] verts;
 
         /** Packed data representing neighbor polygons references and flags for each edge. */
-        public readonly int[] neis;
+        public int[] neis;
 
         /** The user defined polygon flags. */
         public int flags;
diff --git a/src/DotRecast.Detour/DtPolyDetail.cs b/src/DotRecast.Detour/DtPolyDetail.cs
index cd813a4..365eb31 100644
--- a/src/DotRecast.Detour/DtPolyDetail.cs
+++ b/src/DotRecast.Detour/DtPolyDetail.cs
@@ -21,19 +21,19 @@ freely, subject to the following restrictions:
 namespace DotRecast.Detour
 {
     /** Defines the location of detail sub-mesh data within a dtMeshTile. */
-    public readonly struct DtPolyDetail
+    public struct DtPolyDetail
     {
         /** The offset of the vertices in the MeshTile::detailVerts array. */
-        public readonly int vertBase;
+        public int vertBase;
 
         /** The offset of the triangles in the MeshTile::detailTris array. */
-        public readonly int triBase;
+        public int triBase;
 
         /** The number of vertices in the sub-mesh. */
-        public readonly int vertCount;
+        public int vertCount;
 
         /** The number of triangles in the sub-mesh. */
-        public readonly int triCount;
+        public int triCount;
 
         public DtPolyDetail(int vertBase, int triBase, int vertCount, int triCount)
         {
diff --git a/src/DotRecast.Recast.Toolset/RcNavMeshBuildSettings.cs b/src/DotRecast.Recast.Toolset/RcNavMeshBuildSettings.cs
index e0b6906..052c11f 100644
--- a/src/DotRecast.Recast.Toolset/RcNavMeshBuildSettings.cs
+++ b/src/DotRecast.Recast.Toolset/RcNavMeshBuildSettings.cs
@@ -1,5 +1,8 @@
-namespace DotRecast.Recast.Toolset
+using System;
+
+namespace DotRecast.Recast.Toolset
 {
+    [Serializable]
     public class RcNavMeshBuildSettings
     {
         public float cellSize = 0.3f;