/// <summary>
        /// Creates nodes for all the geometry elements in the collada file
        /// </summary>
        void CreateNodeList()
        {
            // create a geometry instance for each geometry that has been created
            for (int i = 0; i < listGeometry.Count; i++)
            {
                string url  = ColladaUtilities.BuildUri(listGeometry[i].ID);
                string name = listGeometry[i].ID;

                Core.ColladaNode node = CreateNode(name, "", name, Enums.ColladaNodeType.NODE);

                node.Add(CreateInstanceGeometry(url, listGeometry[i].Name, new MaterialReferenceList()));

                listNode.Add(node);
            }
        }
        /// <summary>
        /// Creates nodes for all the geometry elements in the collada file
        /// </summary>
        void CreateNodeList()
        {
            // create a list of all the shaders used in the file
            //List<string> shader_list = new List<string>();
            //for (int shader_index = 0; shader_index < shaderInfo.GetShaderCount(); shader_index++)
            //    shader_list.Add(ColladaUtilities.FormatName(Path.GetFileNameWithoutExtension(shaderInfo.GetShaderName(shader_index)), " ", "_"));

            // create a controller instance for each geometry
            for (int i = 0; i < listGeometry.Count; i++)
            {
                string url  = ColladaUtilities.BuildUri(listGeometry[i].ID);
                string name = listGeometry[i].ID;

                Core.ColladaNode node = CreateNode(name, "", name, Enums.ColladaNodeType.NODE);

                node.Add(CreateInstanceGeometry(url, listGeometry[i].Name, new MaterialReferenceList()));

                listNode.Add(node);
            }
        }