diff --git a/Source/SharpNav/Heightfield.cs b/Source/SharpNav/Heightfield.cs
index f56f04da..3f62c741 100644
--- a/Source/SharpNav/Heightfield.cs
+++ b/Source/SharpNav/Heightfield.cs
@@ -61,9 +61,9 @@ public Heightfield(BBox3 b, float cellSize, float cellHeight)
 			this.bounds = b;
 
 			//make sure the bbox contains all the possible voxels.
-			width = (int)Math.Ceiling((b.Max.X - b.Min.X) / cellSize);
-			height = (int)Math.Ceiling((b.Max.Y - b.Min.Y) / cellHeight);
-			length = (int)Math.Ceiling((b.Max.Z - b.Min.Z) / cellSize);
+			width = (int)Math.Round((b.Max.X - b.Min.X) / cellSize);
+			height = (int)Math.Round((b.Max.Y - b.Min.Y) / cellHeight);
+			length = (int)Math.Round((b.Max.Z - b.Min.Z) / cellSize);
 
 			bounds.Max.X = bounds.Min.X + width * cellSize;
 			bounds.Max.Y = bounds.Min.Y + height * cellHeight;
diff --git a/Source/SharpNav/PolyMeshDetail.cs b/Source/SharpNav/PolyMeshDetail.cs
index f62adf7f..9555e3cf 100644
--- a/Source/SharpNav/PolyMeshDetail.cs
+++ b/Source/SharpNav/PolyMeshDetail.cs
@@ -639,7 +639,7 @@ private void BuildPolyDetail(Vector3[] polyMeshVerts, int numMeshVerts, float sa
 			//tessellate outlines
 			if (sampleDist > 0)
 			{
-				for (int i = 0, j = verts.Count - 1; i < verts.Count; j = i++)
+				for (int i = 0, j = numMeshVerts - 1; i < numMeshVerts; j = i++)
 				{
 					Vector3 vi = verts[i];
 					Vector3 vj = verts[j];