/// <summary>
 /// Create the contained materials within the IfcMaterialLayerSetUsage.
 /// </summary>
 /// <param name="doc">The document.</param>
 public void Create(Document doc)
 {
     if (MaterialLayerSet != null)
     {
         MaterialLayerSet.Create(doc);
     }
 }
        /// <summary>
        /// Return the material list for this IFCMaterialSelect.
        /// </summary>
        public IList <IFCMaterial> GetMaterials()
        {
            if (MaterialLayerSet == null)
            {
                return(new List <IFCMaterial>());
            }

            return(MaterialLayerSet.GetMaterials());
        }