diff --git a/src/MeshIO.GLTF/Readers/GltfBinaryReaderBase.cs b/src/MeshIO.GLTF/Readers/GltfBinaryReaderBase.cs
index ff03864..c588d2e 100644
--- a/src/MeshIO.GLTF/Readers/GltfBinaryReaderBase.cs
+++ b/src/MeshIO.GLTF/Readers/GltfBinaryReaderBase.cs
@@ -64,7 +64,7 @@ public Scene Read()
 				Node n = readNode(nodeIndex);
 
 				if (n != null)
-					scene.RootNode.Children.Add(n);
+					scene.RootNode.Nodes.Add(n);
 			}
 
 			return scene;
@@ -118,12 +118,12 @@ protected Node readNode(int index)
 
 			if (gltfNode.Mesh.HasValue)
 			{
-				node.Children.AddRange(readPrimitivesInMesh(gltfNode.Mesh.Value, node));
+				node.Entities.AddRange(readPrimitivesInMesh(gltfNode.Mesh.Value, node));
 			}
 
 			if (gltfNode.Camera.HasValue)
 			{
-				node.Children.Add(readCamera(gltfNode.Camera.Value));
+				node.Entities.Add(readCamera(gltfNode.Camera.Value));
 			}
 
 			gltfNode.Children?.ToList().ForEach((i) =>
@@ -131,7 +131,7 @@ protected Node readNode(int index)
 				Node n = readNode(i);
 
 				if (n != null)
-					node.Children.Add(n);
+					node.Nodes.Add(n);
 			});
 
 			return node;
@@ -166,7 +166,7 @@ protected List<Mesh> readPrimitivesInMesh(int index, Node parent)
 				mesh.Name = gltfMesh.Name;
 				meshes.Add(mesh);
 
-				parent.Children.Add(material);    //TODO: fix the material reference
+				parent.Materials.Add(material);    //TODO: fix the material reference
 			}
 
 			return meshes;
diff --git a/src/MeshIO.STL.Tests/StlWriterTest.cs b/src/MeshIO.STL.Tests/StlWriterTest.cs
index f501fed..294e7ea 100644
--- a/src/MeshIO.STL.Tests/StlWriterTest.cs
+++ b/src/MeshIO.STL.Tests/StlWriterTest.cs
@@ -23,7 +23,7 @@ static StlWriterTest()
 			XYZ v2 = new XYZ(0, 1, 0);
 			XYZ v3 = new XYZ(1, 1, 0);
 
-			_mesh.AddTriangles(v1, v2, v3);
+			_mesh.AddPolygons(v1, v2, v3);
 			_mesh.Layers.GetLayer<LayerElementNormal>().Normals.Add(new XYZ(0, 0, 1));
 		}
 
diff --git a/src/MeshIO.STL/StlReader.cs b/src/MeshIO.STL/StlReader.cs
index 051978c..d5d09ec 100644
--- a/src/MeshIO.STL/StlReader.cs
+++ b/src/MeshIO.STL/StlReader.cs
@@ -86,7 +86,7 @@ public Mesh Read()
 					XYZ v2 = new XYZ(this._stream.ReadSingle(), this._stream.ReadSingle(), this._stream.ReadSingle());
 					XYZ v3 = new XYZ(this._stream.ReadSingle(), this._stream.ReadSingle(), this._stream.ReadSingle());
 
-					mesh.AddTriangles(v1, v2, v3);
+					mesh.AddPolygons(v1, v2, v3);
 
 					ushort attByteCount = this._stream.ReadUShort();
 				}
@@ -112,7 +112,7 @@ public Mesh Read()
 					XYZ v2 = this.readPoint(this._stream.ReadUntil('\n'), "vertex");
 					XYZ v3 = this.readPoint(this._stream.ReadUntil('\n'), "vertex");
 
-					mesh.AddTriangles(v1, v2, v3);
+					mesh.AddPolygons(v1, v2, v3);
 
 					this.checkLine(this._stream.ReadUntil('\n'), "endloop");
 					this.checkLine(this._stream.ReadUntil('\n'), "endfacet");
diff --git a/src/MeshIO/Entities/Geometries/Layers/LayerElement.cs b/src/MeshIO/Entities/Geometries/Layers/LayerElement.cs
index c16b3e7..a7a482d 100644
--- a/src/MeshIO/Entities/Geometries/Layers/LayerElement.cs
+++ b/src/MeshIO/Entities/Geometries/Layers/LayerElement.cs
@@ -27,11 +27,5 @@ public LayerElement(MappingMode mappingMode, ReferenceMode referenceMode)
 			this.MappingMode = mappingMode;
 			this.ReferenceMode = referenceMode;
 		}
-
-		[Obsolete]
-		public LayerElement(Geometry owner) : this()
-		{
-			this.Owner = owner;
-		}
 	}
 }
diff --git a/src/MeshIO/Entities/Geometries/Mesh.cs b/src/MeshIO/Entities/Geometries/Mesh.cs
index 3fbb56d..e8ce5d8 100644
--- a/src/MeshIO/Entities/Geometries/Mesh.cs
+++ b/src/MeshIO/Entities/Geometries/Mesh.cs
@@ -15,12 +15,30 @@ public Mesh() : base() { }
 
 		public Mesh(string name) : base(name) { }
 
-		[Obsolete]
-		public void AddTriangles(params XYZ[] vertices)
+		/// <summary>
+		/// 
+		/// </summary>
+		/// <param name="vertices"></param>
+		/// <exception cref="ArgumentException"></exception>
+		public void AddPolygons(params XYZ[] vertices)
 		{
-			if (vertices.Count() % 3 != 0)
-				throw new ArgumentException("The array of vertices should be multiple of 3", nameof(vertices));
+			int count = vertices.Count();
+			if (vertices.Count() % 3 == 0)
+			{
+				this.addTriangles(vertices);
+			}
+			else if (vertices.Count() % 4 == 0)
+			{
+				this.addQuads(vertices);
+			}
+			else
+			{
+				throw new ArgumentException("The array of vertices should be multiple of 3 or 4", nameof(vertices));
+			}
+		}
 
+		private void addTriangles(XYZ[] vertices)
+		{
 			if (this.Polygons.Any() && this.Polygons.First().GetType() != typeof(Triangle))
 				throw new ArgumentException("This mesh is not formed by Triangles");
 
@@ -38,5 +56,25 @@ public void AddTriangles(params XYZ[] vertices)
 			}
 		}
 
+		private void addQuads(XYZ[] vertices)
+		{
+			if (this.Polygons.Any() && this.Polygons.First().GetType() != typeof(Quad))
+				throw new ArgumentException("This mesh is not formed by Quads");
+
+			for (int i = 0; i < vertices.Count(); i += 4)
+			{
+				this.Vertices.Add(vertices.ElementAt(i));
+				this.Vertices.Add(vertices.ElementAt(i + 1));
+				this.Vertices.Add(vertices.ElementAt(i + 2));
+				this.Vertices.Add(vertices.ElementAt(i + 3));
+
+				this.Polygons.Add(new Quad(
+						this.Vertices.Count - 4,
+						this.Vertices.Count - 3,
+						this.Vertices.Count - 2,
+						this.Vertices.Count - 1
+					));
+			}
+		}
 	}
 }
diff --git a/src/MeshIO/Node.cs b/src/MeshIO/Node.cs
index 6639b94..b0a5a44 100644
--- a/src/MeshIO/Node.cs
+++ b/src/MeshIO/Node.cs
@@ -7,9 +7,6 @@ namespace MeshIO
 {
 	public class Node : SceneElement
 	{
-		[Obsolete]
-		public bool Shading { get; set; } = true;
-
 		/// <summary>
 		/// The node and all the components are visible or not
 		/// </summary>
@@ -25,12 +22,6 @@ public class Node : SceneElement
 		/// </summary>
 		public Element3D Parent { get; }
 
-		/// <summary>
-		/// Get all linked elements to this node
-		/// </summary>
-		[Obsolete("Replace for the different collections, ")]
-		public List<Element3D> Children { get; } = new();
-
 		public List<Node> Nodes { get; } = new();
 
 		public List<Material> Materials { get; } = new();