diff --git a/FieldVisualizer/ViewModels/FieldViewerViewModels/FieldViewerViewModel.cs b/FieldVisualizer/ViewModels/FieldViewerViewModels/FieldViewerViewModel.cs
index ceddfa4..4f16ce6 100644
--- a/FieldVisualizer/ViewModels/FieldViewerViewModels/FieldViewerViewModel.cs
+++ b/FieldVisualizer/ViewModels/FieldViewerViewModels/FieldViewerViewModel.cs
@@ -54,11 +54,19 @@ namespace FieldVisualizer.ViewModels.FieldViewerViewModels
             {
                 primitiveSet = value;
                 OnPropertyChanged(nameof(PrimitiveSet));
+                AreaTotal = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Sum(x => x.Area);
+                OnPropertyChanged(nameof(AreaTotal));
+                AreaNeg = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value < 0d).Sum(x => x.Area);
+                OnPropertyChanged(nameof(AreaNeg));
+                AreaZero = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value == 0d).Sum(x => x.Area);
+                OnPropertyChanged(nameof(AreaZero));
+                AreaPos = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value > 0d).Sum(x => x.Area);
+                OnPropertyChanged(nameof(AreaPos));
                 SumTotal = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Sum(x => x.Value);
                 OnPropertyChanged(nameof(SumTotal));
-                SumNeg = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value < 0).Sum(x => x.Value);
+                SumNeg = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value < 0d).Sum(x => x.Value);
                 OnPropertyChanged(nameof(SumNeg));
-                SumPos = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value > 0).Sum(x => x.Value);
+                SumPos = primitiveSet is null ? 0 : primitiveSet.ValuePrimitives.Where(x => x.Value > 0d).Sum(x => x.Value);
                 OnPropertyChanged(nameof(SumPos));
 
             }
@@ -122,6 +130,10 @@ namespace FieldVisualizer.ViewModels.FieldViewerViewModels
                 }
             }
         }
+        public double AreaTotal { get; private set; }
+        public double AreaNeg { get; private set; }
+        public double AreaZero { get; private set; }
+        public double AreaPos { get; private set; }
         public double SumTotal { get; private set;}
         public double SumNeg { get; private set; }
         public double SumPos { get; private set; }
diff --git a/FieldVisualizer/Windows/UserControls/FieldViewer.xaml b/FieldVisualizer/Windows/UserControls/FieldViewer.xaml
index 23fdb96..0fbb914 100644
--- a/FieldVisualizer/Windows/UserControls/FieldViewer.xaml
+++ b/FieldVisualizer/Windows/UserControls/FieldViewer.xaml
@@ -52,6 +52,14 @@
                 </Expander>
                 <Expander Header="Summary information" IsExpanded="False">
                     <StackPanel>
+                        <TextBlock Text="Total area:"/>
+                        <TextBlock Text="{Binding AreaTotal}"/>
+                        <TextBlock Text="Negative value area:"/>
+                        <TextBlock Text="{Binding AreaNeg}"/>
+                        <TextBlock Text="Zero value area:"/>
+                        <TextBlock Text="{Binding AreaZero}"/>
+                        <TextBlock Text="Positive value area:"/>
+                        <TextBlock Text="{Binding AreaPos}"/>
                         <TextBlock Text="Total sum: "/>
                         <TextBlock Text="{Binding SumTotal}"/>
                         <TextBlock Text="Sum negative: "/>
diff --git a/Libraries/LoaderCalculator.dll b/Libraries/LoaderCalculator.dll
index db17b24..5e7cddf 100644
Binary files a/Libraries/LoaderCalculator.dll and b/Libraries/LoaderCalculator.dll differ
diff --git a/StructureHelperLogics/Models/Materials/ElasticMaterial.cs b/StructureHelperLogics/Models/Materials/ElasticMaterial.cs
index f7b4e8d..9a6b509 100644
--- a/StructureHelperLogics/Models/Materials/ElasticMaterial.cs
+++ b/StructureHelperLogics/Models/Materials/ElasticMaterial.cs
@@ -15,7 +15,17 @@ namespace StructureHelperLogics.Models.Materials
 
         public IMaterial GetLoaderMaterial(LimitStates limitState, CalcTerms calcTerm)
         {
-            throw new NotImplementedException();
+            IMaterial material = new Material();
+            material.InitModulus = Modulus;
+            IEnumerable<double> parameters = new List<double>() { Modulus};
+            material.DiagramParameters = parameters;
+            material.Diagram = GetStress;
+            return material;
+        }
+
+        private double GetStress (IEnumerable<double> parameters, double strain)
+        {
+            return parameters.First() * strain;
         }
 
         public object Clone()
diff --git a/Windows/CalculationWindows/CalculationPropertyWindow/CalculationPropertyView.xaml b/Windows/CalculationWindows/CalculationPropertyWindow/CalculationPropertyView.xaml
index 1165519..91e7987 100644
--- a/Windows/CalculationWindows/CalculationPropertyWindow/CalculationPropertyView.xaml
+++ b/Windows/CalculationWindows/CalculationPropertyWindow/CalculationPropertyView.xaml
@@ -24,8 +24,12 @@
         </Grid.RowDefinitions>
         <TabControl>
             <TabItem Header="Forces">
-                <StackPanel>
-                    <GroupBox Header="Combinations of forces" Height="160">
+                <Grid>
+                    <Grid.RowDefinitions>
+                        <RowDefinition/>
+                        <RowDefinition Height="80"/>
+                    </Grid.RowDefinitions>
+                    <GroupBox Grid.Row="0" Header="Combinations of forces" Height="160">
                         <Grid>
                             <Grid.ColumnDefinitions>
                                 <ColumnDefinition Width="*"/>
@@ -46,7 +50,7 @@
                             </StackPanel>
                         </Grid>
                     </GroupBox>
-                    <Grid Height="80">
+                    <Grid Grid.Row="1" Height="80">
                         <Grid.ColumnDefinitions>
                             <ColumnDefinition/>
                             <ColumnDefinition/>
@@ -64,7 +68,7 @@
                             </StackPanel>
                         </GroupBox>
                     </Grid>
-                </StackPanel>
+                </Grid>
             </TabItem>
             <TabItem Header="Iterations">
                 <Grid>
diff --git a/Windows/MainWindow/MainView.xaml b/Windows/MainWindow/MainView.xaml
index 77ff00f..6725caa 100644
--- a/Windows/MainWindow/MainView.xaml
+++ b/Windows/MainWindow/MainView.xaml
@@ -48,6 +48,7 @@
                 </MenuItem>
                 <Button Content="Materials" Command="{Binding EditHeadMaterialsCommand}"/>
                 <Button Content="Calculation properties" Command="{Binding Path=EditCalculationPropertyCommand}"/>
+                <Button Content="Move primitives to center" Command="{Binding Path=MovePrimitiveToGravityCenterCommand}"/>
                 <MenuItem Header="Templates">
                     <Button Content="Concrete beam" Command="{Binding AddBeamCase}"/>
                     <Button Content="Concrete column" Command="{Binding AddColumnCase}"/>
diff --git a/Windows/MainWindow/MainViewModel.cs b/Windows/MainWindow/MainViewModel.cs
index fac1610..15a8032 100644
--- a/Windows/MainWindow/MainViewModel.cs
+++ b/Windows/MainWindow/MainViewModel.cs
@@ -1,4 +1,5 @@
 using LoaderCalculator.Data.Ndms;
+using LoaderCalculator.Logics.Geometry;
 using StructureHelper.Infrastructure;
 using StructureHelper.Infrastructure.Enums;
 using StructureHelper.Infrastructure.UI.DataContexts;
@@ -25,6 +26,7 @@ using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
+using System.Security.Cryptography;
 using System.Windows.Forms;
 using System.Windows.Input;
 
@@ -133,6 +135,7 @@ namespace StructureHelper.Windows.MainWindow
         public ICommand AddSlabCase { get; }
         public ICommand LeftButtonDown { get; }
         public ICommand LeftButtonUp { get; }
+        public ICommand MovePrimitiveToGravityCenterCommand { get; }
         public ICommand PreviewMouseMove { get; }
         public ICommand ClearSelection { get; }
         public ICommand OpenMaterialCatalog { get; }
@@ -313,10 +316,25 @@ namespace StructureHelper.Windows.MainWindow
             Calculate = new RelayCommand(o =>
             {
                 CalculateResult();
-            });
+
+            },
+            o => Model.PrimitiveRepository.Primitives.Count() > 0);
 
             EditCalculationPropertyCommand = new RelayCommand (o => EditCalculationProperty());
 
+            MovePrimitiveToGravityCenterCommand = new RelayCommand(o =>
+            {
+                IEnumerable<INdm> ndms = Model.GetNdms(calculationProperty);
+                double[] center = GeometryOperations.GetGravityCenter(ndms);
+                foreach (var primitive in Model.PrimitiveRepository.Primitives)
+                {
+                    primitive.CenterX -= center[0];
+                    primitive.CenterY -= center[1];
+                }
+            },
+            o => Model.PrimitiveRepository.Primitives.Count() > 0
+            );
+
             SetPopupCanBeClosedTrue = new RelayCommand(o =>
             {
                 if (!(o is PrimitiveBase primitive)) return;
@@ -345,8 +363,8 @@ namespace StructureHelper.Windows.MainWindow
                 var dialogResult = MessageBox.Show("Delete primitive?", "Please, confirm deleting", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
                 if (dialogResult == DialogResult.Yes)
                 {
-                    Primitives.Remove(SelectedPrimitive);
                     PrimitiveRepository.Delete(SelectedPrimitive);
+                    Primitives.Remove(SelectedPrimitive);                   
                 }
             }
             else { MessageBox.Show("Selection is changed", "Please, select primitive", MessageBoxButtons.YesNo, MessageBoxIcon.Warning); }