Index: dam clients/DamUI/trunk/src/Dam/Data/DamEngineIo/FillXmlInputFromDamUi.cs
===================================================================
diff -u -r646 -r666
--- dam clients/DamUI/trunk/src/Dam/Data/DamEngineIo/FillXmlInputFromDamUi.cs	(.../FillXmlInputFromDamUi.cs)	(revision 646)
+++ dam clients/DamUI/trunk/src/Dam/Data/DamEngineIo/FillXmlInputFromDamUi.cs	(.../FillXmlInputFromDamUi.cs)	(revision 666)
@@ -144,6 +144,20 @@
             {
                 throw new NullReferenceException("No surfacelines defined in this project");
             }
+            else
+            {
+                foreach (var surfaceLine in dike.SurfaceLines2)
+                {
+                    if ((surfaceLine.CharacteristicPoints == null) || (surfaceLine.CharacteristicPoints.Count < 1))
+                    {
+                        throw new NullReferenceException($"Surfaceline '{surfaceLine.Name}' has no characteristic points");
+                    }
+                    if ((surfaceLine.Geometry == null) || (surfaceLine.Geometry.Count < 2))
+                    {
+                        throw new NullReferenceException($"Surfaceline '{surfaceLine.Name}' has no points");
+                    }
+                }
+            }
             if (dike.SoilList == null)
             {
                 throw new NullReferenceException("No soils defined in this project");
Index: dam clients/DamUI/trunk/src/Dam/Data/DamEngineIo/FillDamUiFromXmlInput.cs
===================================================================
diff -u -r636 -r666
--- dam clients/DamUI/trunk/src/Dam/Data/DamEngineIo/FillDamUiFromXmlInput.cs	(.../FillDamUiFromXmlInput.cs)	(revision 636)
+++ dam clients/DamUI/trunk/src/Dam/Data/DamEngineIo/FillDamUiFromXmlInput.cs	(.../FillDamUiFromXmlInput.cs)	(revision 666)
@@ -110,6 +110,16 @@
             {
                 throw new NullReferenceException("No surfacelines defined in the input");
             }
+            else
+            {
+                foreach (var surfaceLine in input.SurfaceLines)
+                {
+                    if ((surfaceLine.Points == null) || (surfaceLine.Points.Length < 1))
+                    {
+                        throw new NullReferenceException($"Surfaceline '{surfaceLine.Name}' has no points");
+                    }
+                }
+            }
             if (input.Soils == null)
             {
                 throw new NullReferenceException("No soils defined in the input");