Objects of NdmElement were added

StructureHelperLogics/NdmCalculations/Primitives/INdmElement.cs

@@ -0,0 +1,37 @@
+using StructureHelper.Models.Materials;
+using StructureHelperCommon.Infrastructures.Interfaces;
+using StructureHelperCommon.Models.Forces;
+using StructureHelperCommon.Models.Shapes;
+using StructureHelperLogics.Models.CrossSections;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperLogics.NdmCalculations.Primitives
+{
+    public interface INdmElement : ISaveable, ICloneable
+    {
+        /// <summary>
+        /// Base point of primitive
+        /// </summary>
+        IPoint2D Center { get; }
+        /// <summary>
+        /// Material of primitive
+        /// </summary>
+        IHeadMaterial? HeadMaterial { get; set; }
+        /// <summary>
+        /// Flag of triangulation
+        /// </summary>
+        bool Triangulate { get; set; }
+        /// <summary>
+        /// Prestrain assigned from user
+        /// </summary>
+        StrainTuple UsersPrestrain { get; }
+        /// <summary>
+        /// Prestrain assigned from calculations
+        /// </summary>
+        StrainTuple AutoPrestrain { get; }
+    }
+}