Index: src/Deltares.DSoilModel.Forms/DrawingCPT.cs
===================================================================
diff -u -r6 -r383
--- src/Deltares.DSoilModel.Forms/DrawingCPT.cs	(.../DrawingCPT.cs)	(revision 6)
+++ src/Deltares.DSoilModel.Forms/DrawingCPT.cs	(.../DrawingCPT.cs)	(revision 383)
@@ -229,35 +229,38 @@
             qcPoints.Clear();
             frictionPoints.Clear();
             waterPressurePoints.Clear();
-            double qcVoid = conePenetrationTestData.qcVoid;
-            double frictionVoid = conePenetrationTestData.FrictionVoid;
-            double waterPressureVoid = conePenetrationTestData.WaterPressureVoid;
+            if (conePenetrationTestData != null)
+            {
+                double qcVoid = conePenetrationTestData.qcVoid;
+                double frictionVoid = conePenetrationTestData.FrictionVoid;
+                double waterPressureVoid = conePenetrationTestData.WaterPressureVoid;
 
-            double dataQcMax = 0, dataFrictionMax = 0, dataWaterPressureMax = 0;
+                double dataQcMax = 0, dataFrictionMax = 0, dataWaterPressureMax = 0;
 
-            // auto scale the axes ?
-            foreach (var row in conePenetrationTestData.CPTDatarows)
-            {
-                // note: sometimes the void values are inconsistent !
-                if (row.qc != qcVoid && row.qc != frictionVoid)
+                // auto scale the axes ?
+                foreach (var row in conePenetrationTestData.CPTDatarows)
                 {
-                    qcPoints.Add(new Point3D(row.qc, 0d, row.Level));
-                    dataQcMax = Math.Max(dataQcMax, row.qc);
+                    // note: sometimes the void values are inconsistent !
+                    if (row.qc != qcVoid && row.qc != frictionVoid)
+                    {
+                        qcPoints.Add(new Point3D(row.qc, 0d, row.Level));
+                        dataQcMax = Math.Max(dataQcMax, row.qc);
+                    }
+                    if (row.friction != frictionVoid && row.friction != qcVoid && conePenetrationTestData.ConeType != ConeType.Ball)
+                    {
+                        frictionPoints.Add(new Point3D(row.friction, 0d, row.Level));
+                        dataFrictionMax = Math.Max(dataFrictionMax, row.friction);
+                    }
+                    if (row.WaterPressureSpecified && row.WaterPressure != waterPressureVoid && conePenetrationTestData.ConeType != ConeType.Ball)
+                    {
+                        waterPressurePoints.Add(new Point3D(row.WaterPressure, 0d, row.Level));
+                        dataWaterPressureMax = Math.Max(dataWaterPressureMax, row.WaterPressure);
+                    }
                 }
-                if (row.friction != frictionVoid && row.friction != qcVoid && conePenetrationTestData.ConeType != ConeType.Ball)
-                {
-                    frictionPoints.Add(new Point3D(row.friction, 0d, row.Level));
-                    dataFrictionMax = Math.Max(dataFrictionMax, row.friction);
-                }
-                if (row.WaterPressureSpecified && row.WaterPressure != waterPressureVoid && conePenetrationTestData.ConeType != ConeType.Ball)
-                {
-                    waterPressurePoints.Add(new Point3D(row.WaterPressure, 0d, row.Level));
-                    dataWaterPressureMax = Math.Max(dataWaterPressureMax, row.WaterPressure);
-                }
+                qcMax = (qcMax == 0) ? dataQcMax : qcMax;
+                frictionMax = (frictionMax == 0) ? dataFrictionMax : frictionMax;
+                waterPressureMax = (waterPressureMax == 0) ? dataWaterPressureMax : waterPressureMax;
             }
-            qcMax = (qcMax == 0) ? dataQcMax : qcMax;
-            frictionMax = (frictionMax == 0) ? dataFrictionMax : frictionMax;
-            waterPressureMax = (waterPressureMax == 0) ? dataWaterPressureMax : waterPressureMax;
         }
 
         /// <summary>