Index: Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Calculator/IHydraulicLoadsCalculator.cs
===================================================================
diff -u -r889e8e4ee8267b316e00e8f8a1035c60afb200a0 -rd02c314b35f0c122d7ac466dbe384e6b2707a1fd
--- Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Calculator/IHydraulicLoadsCalculator.cs	(.../IHydraulicLoadsCalculator.cs)	(revision 889e8e4ee8267b316e00e8f8a1035c60afb200a0)
+++ Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Calculator/IHydraulicLoadsCalculator.cs	(.../IHydraulicLoadsCalculator.cs)	(revision d02c314b35f0c122d7ac466dbe384e6b2707a1fd)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using Ringtoets.HydraRing.Calculation.Data.Input.Hydraulics;
 using Ringtoets.HydraRing.Calculation.Data.Output.IllustrationPoints;
 using Ringtoets.HydraRing.Calculation.Exceptions;
@@ -72,6 +73,7 @@
         /// <param name="input">The <see cref="HydraulicLoadsCalculationInput"/> which contains all the necessary input
         /// for the calculation.</param>
         /// <exception cref="HydraRingCalculationException">Thrown when an error occurs while performing the calculation.</exception>
+        /// <exception cref="InvalidOperationException">Thrown when preprocessor directory is required but not specified.</exception>
         void Calculate(HydraulicLoadsCalculationInput input);
 
         /// <summary>