diff --git a/corsika/detail/framework/process/InteractionLengthModifier.inl b/corsika/detail/framework/process/InteractionLengthModifier.inl
new file mode 100644
index 0000000000000000000000000000000000000000..a11c22ee4ca9fdd0dc7720f3cdd45d5431a1d4d9
--- /dev/null
+++ b/corsika/detail/framework/process/InteractionLengthModifier.inl
@@ -0,0 +1,54 @@
+/*
+ * (c) Copyright 2021 CORSIKA Project, corsika-project@lists.kit.edu
+ *
+ * This software is distributed under the terms of the GNU General Public
+ * Licence version 3 (GPL Version 3). See file LICENSE for a full version of
+ * the license.
+ */
+
+#pragma once
+
+#include <utility>
+
+#include <corsika/framework/core/ParticleProperties.hpp>
+#include <corsika/framework/core/PhysicalUnits.hpp>
+
+namespace corsika {
+
+  template <class TUnderlyingProcess>
+  inline InteractionLengthModifier<TUnderlyingProcess>::InteractionLengthModifier(
+      TUnderlyingProcess&& process,
+      std::function<InteractionLengthModifier::functor_signature> modifier)
+      : process_{std::move(process)}
+      , modifier_{std::move(modifier)} {}
+
+  template <class TUnderlyingProcess>
+  template <typename TSecondaryView>
+  inline void InteractionLengthModifier<TUnderlyingProcess>::doInteraction(
+      TSecondaryView& view) {
+    process_.doInteraction(view);
+  }
+
+  template <class TUnderlyingProcess>
+  template <typename TParticle>
+  inline GrammageType InteractionLengthModifier<TUnderlyingProcess>::getInteractionLength(
+      TParticle const& particle) {
+    GrammageType const original = process_.getInteractionLength(particle);
+    Code const pid = particle.getPID();
+    HEPEnergyType const energy = particle.getEnergy();
+
+    return modifier_(original, pid, energy);
+  }
+
+  template <class TUnderlyingProcess>
+  inline TUnderlyingProcess const&
+  InteractionLengthModifier<TUnderlyingProcess>::getProcess() const {
+    return process_;
+  }
+
+  template <class TUnderlyingProcess>
+  inline TUnderlyingProcess& InteractionLengthModifier<TUnderlyingProcess>::getProcess() {
+    return process_;
+  }
+
+} // namespace corsika
diff --git a/corsika/framework/process/InteractionLengthModifier.hpp b/corsika/framework/process/InteractionLengthModifier.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..d9013033e9b1b1716925c2110477d95e7a3176b1
--- /dev/null
+++ b/corsika/framework/process/InteractionLengthModifier.hpp
@@ -0,0 +1,66 @@
+/*
+ * (c) Copyright 2021 CORSIKA Project, corsika-project@lists.kit.edu
+ *
+ * This software is distributed under the terms of the GNU General Public
+ * Licence version 3 (GPL Version 3). See file LICENSE for a full version of
+ * the license.
+ */
+
+#pragma once
+
+#include <functional>
+
+#include <corsika/framework/core/ParticleProperties.hpp>
+#include <corsika/framework/core/PhysicalUnits.hpp>
+#include <corsika/framework/process/InteractionProcess.hpp>
+
+namespace corsika {
+  /*!
+    @ingroup Processes
+    @{
+
+   * Wrapper around an InteractionProcess that allows modifying the interaction
+   * length returned by the underlying process in a user-defined way.   *
+   */
+  template <class TUnderlyingProcess>
+  class InteractionLengthModifier
+      : public InteractionProcess<InteractionLengthModifier<TUnderlyingProcess>> {
+
+    //! identity function as default modifier
+    static auto constexpr non_modifying_functor = [](GrammageType original, corsika::Code,
+                                                     HEPEnergyType) { return original; };
+
+  public:
+    //! The signature of the modifying functor. Arguments are original int. length, PID,
+    //! energy
+    using functor_signature = GrammageType(GrammageType, corsika::Code, HEPEnergyType);
+
+    /**
+     * Create wrapper around InteractionProcess. Note that the passed process object
+     * itself may no longer be used, only through this class.
+     */
+    InteractionLengthModifier(TUnderlyingProcess&& process,
+                              std::function<functor_signature> modifier);
+
+    //! wrapper around internal process doInteraction
+    template <typename TSecondaryView>
+    void doInteraction(TSecondaryView& view);
+
+    ///! returns underlying process getInteractionLength modified
+    template <typename TParticle>
+    GrammageType getInteractionLength(TParticle const& particle);
+
+    ///! obtain reference to wrapped process
+    TUnderlyingProcess const& getProcess() const;
+    TUnderlyingProcess& getProcess();
+
+  private:
+    TUnderlyingProcess process_;
+    std::function<functor_signature> const modifier_{non_modifying_functor};
+  };
+
+  //! @}
+
+} // namespace corsika
+
+#include <corsika/detail/framework/process/InteractionLengthModifier.inl>
diff --git a/tests/framework/CMakeCache.txt b/tests/framework/CMakeCache.txt
deleted file mode 100644
index 792df53c17d42a1b2a9f008c4c4450be089dbfec..0000000000000000000000000000000000000000
--- a/tests/framework/CMakeCache.txt
+++ /dev/null
@@ -1,342 +0,0 @@
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diff --git a/tests/framework/CMakeLists.txt b/tests/framework/CMakeLists.txt
index 829709779bd7ec19b8b9fb0037422a1f6ca105da..7d67ad5aafd1f64314fa67ff4d9ed95b34ba442e 100644
--- a/tests/framework/CMakeLists.txt
+++ b/tests/framework/CMakeLists.txt
@@ -20,6 +20,7 @@ set (test_framework_sources
   testNullModel.cpp  
   testHelix.cpp
   testInteractionCounter.cpp
+  testInteractionLengthModifier.cpp
   testSolver.cpp
   )
 
diff --git a/tests/framework/testInteractionLengthModifier.cpp b/tests/framework/testInteractionLengthModifier.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..5d8ee70ed26ec29ff53c540cc2533e4b6b556668
--- /dev/null
+++ b/tests/framework/testInteractionLengthModifier.cpp
@@ -0,0 +1,73 @@
+/*
+ * (c) Copyright 2018 CORSIKA Project, corsika-project@lists.kit.edu
+ *
+ * This software is distributed under the terms of the GNU General Public
+ * Licence version 3 (GPL Version 3). See file LICENSE for a full version of
+ * the license.
+ */
+
+#include <corsika/framework/process/InteractionLengthModifier.hpp>
+#include <corsika/framework/core/PhysicalUnits.hpp>
+
+#include <catch2/catch.hpp>
+
+using namespace corsika;
+
+struct DummyProcess : public InteractionProcess<DummyProcess> {
+  int id{0};
+
+  template <typename TParticle>
+  GrammageType getInteractionLength(TParticle const&) {
+    return 100_g / 1_cm / 1_cm;
+  }
+
+  template <typename TArgument>
+  void doInteraction(TArgument& arg) {
+    arg = 3;
+  }
+
+  DummyProcess() = default;
+  DummyProcess(DummyProcess&&) = default;
+
+  // prevent copying
+  DummyProcess(DummyProcess const&) = delete;
+  DummyProcess& operator=(DummyProcess const&) = delete;
+};
+
+struct DummyParticle {
+  HEPEnergyType getEnergy() const { return 47_TeV; }
+
+  Code getPID() const { return Code::MuPlus; }
+};
+
+TEST_CASE("InteractionLengthModifier", "[process]") {
+  DummyProcess u;
+  u.id = 38;
+
+  auto const modifier = [](GrammageType orig, Code, HEPEnergyType) -> GrammageType {
+    return orig * 2;
+  };
+
+  InteractionLengthModifier mod{std::move(u), modifier};
+  REQUIRE(std::is_same_v<decltype(mod), InteractionLengthModifier<DummyProcess>>);
+
+  SECTION("getInteractionLength") {
+    DummyParticle const p;
+    REQUIRE(mod.getInteractionLength(p) == 200_g / 1_cm / 1_cm);
+  }
+
+  SECTION("doInteraction") {
+    int k = 0;
+    mod.doInteraction(k);
+    REQUIRE(k == 3);
+  }
+
+  SECTION("getProcess") {
+    DummyProcess& uRef = mod.getProcess();
+    REQUIRE(uRef.id == 38);
+
+    decltype(mod) const& modConstRef = mod;
+    DummyProcess const& uConstRef = modConstRef.getProcess();
+    REQUIRE(uConstRef.id == 38);
+  }
+}