diff --git a/include/RMGHardware.hh b/include/RMGHardware.hh
index b1852f4b..01ddc406 100644
--- a/include/RMGHardware.hh
+++ b/include/RMGHardware.hh
@@ -75,6 +75,7 @@ class RMGHardware : public G4VUserDetectorConstruction {
 
     /// List of GDML files to load
     std::vector<std::string> fGDMLFiles;
+    bool fGDMLDisableOverlapCheck = false;
     /// Mapping between physical volume names and maximum (user) step size to apply
     std::map<std::string, double> fPhysVolStepLimits;
 
diff --git a/include/RMGRunAction.hh b/include/RMGRunAction.hh
index 622e6757..53a39463 100644
--- a/include/RMGRunAction.hh
+++ b/include/RMGRunAction.hh
@@ -48,6 +48,8 @@ class RMGRunAction : public G4UserRunAction {
     void BeginOfRunAction(const G4Run*) override;
     void EndOfRunAction(const G4Run*) override;
 
+    inline int GetCurrentRunPrintModulo() const { return fCurrentPrintModulo; }
+
     inline auto& GetOutputDataFields(RMGHardware::DetectorType d_type) {
       return fOutputDataFields.at(d_type);
     }
@@ -62,6 +64,8 @@ class RMGRunAction : public G4UserRunAction {
     bool fIsAnaManInitialized = false;
     RMGMasterGenerator* fRMGMasterGenerator = nullptr;
 
+    int fCurrentPrintModulo = -1;
+
     std::map<RMGHardware::DetectorType, std::unique_ptr<RMGVOutputScheme>> fOutputDataFields;
 };
 
diff --git a/src/RMGEventAction.cc b/src/RMGEventAction.cc
index 0fa76f9a..c4828b01 100644
--- a/src/RMGEventAction.cc
+++ b/src/RMGEventAction.cc
@@ -36,7 +36,7 @@ RMGEventAction::RMGEventAction(RMGRunAction* run_action) : fRunAction(run_action
 
 void RMGEventAction::BeginOfEventAction(const G4Event* event) {
 
-  auto print_modulo = RMGManager::Instance()->GetPrintModulo();
+  auto print_modulo = fRunAction->GetCurrentRunPrintModulo();
   if ((event->GetEventID() + 1) % print_modulo == 0) {
 
     auto current_run = dynamic_cast<const RMGRun*>(G4RunManager::GetRunManager()->GetCurrentRun());
diff --git a/src/RMGHardware.cc b/src/RMGHardware.cc
index b86418ac..82e7ed29 100644
--- a/src/RMGHardware.cc
+++ b/src/RMGHardware.cc
@@ -43,7 +43,7 @@ G4VPhysicalVolume* RMGHardware::Construct() {
   if (!fGDMLFiles.empty()) {
     RMGLog::Out(RMGLog::debug, "Setting up G4GDMLParser");
     G4GDMLParser parser;
-    parser.SetOverlapCheck(true);
+    parser.SetOverlapCheck(!fGDMLDisableOverlapCheck);
     for (const auto& file : fGDMLFiles) {
       RMGLog::Out(RMGLog::detail, "Reading ", file, " GDML file");
       if (!fs::exists(fs::path(file.data()))) RMGLog::Out(RMGLog::fatal, file, " does not exist");
@@ -58,8 +58,6 @@ G4VPhysicalVolume* RMGHardware::Construct() {
           "Did you forget to reimplement the base class method, or to specify a GDML file?");
   }
 
-  // TODO: build and return world volume?
-
   // attach user max step sizes to logical volumes
   for (const auto& el : fPhysVolStepLimits) {
     RMGLog::OutFormat(RMGLog::debug, "Setting max user step size for volume '{}' to {}", el.first,
@@ -190,6 +188,11 @@ void RMGHardware::DefineCommands() {
   fMessenger = std::make_unique<G4GenericMessenger>(this, "/RMG/Geometry/",
       "Commands for controlling geometry definitions");
 
+  fMessenger->DeclareProperty("GDMLDisableOverlapCheck", fGDMLDisableOverlapCheck)
+      .SetGuidance("Disable the automatic overlap check after loading a GDML file")
+      .SetStates(G4State_PreInit)
+      .SetToBeBroadcasted(false);
+
   fMessenger->DeclareMethod("IncludeGDMLFile", &RMGHardware::IncludeGDMLFile)
       .SetGuidance("Use GDML file for geometry definition")
       .SetParameterName("filename", false)
diff --git a/src/RMGRunAction.cc b/src/RMGRunAction.cc
index 938760f7..b6eeccda 100644
--- a/src/RMGRunAction.cc
+++ b/src/RMGRunAction.cc
@@ -138,9 +138,10 @@ void RMGRunAction::BeginOfRunAction(const G4Run*) {
 
   auto g4manager = G4RunManager::GetRunManager();
   auto tot_events = g4manager->GetNumberOfEventsToBeProcessed();
-  if (manager->GetPrintModulo() <= 0 and tot_events >= 100)
-    manager->SetPrintModulo(tot_events / 10);
-  else if (tot_events < 100) manager->SetPrintModulo(100);
+
+  fCurrentPrintModulo = manager->GetPrintModulo();
+  if (fCurrentPrintModulo <= 0 and tot_events >= 100) fCurrentPrintModulo = tot_events / 10;
+  else if (tot_events < 100) fCurrentPrintModulo = 100;
 }
 
 void RMGRunAction::EndOfRunAction(const G4Run*) {
@@ -203,10 +204,6 @@ void RMGRunAction::EndOfRunAction(const G4Run*) {
     G4AnalysisManager::Instance()->Write();
     G4AnalysisManager::Instance()->CloseFile();
   }
-
-  // reset print modulo
-  // TODO: if it's user specified, it shouldn't be reset
-  RMGManager::Instance()->SetPrintModulo(-1);
 }
 
 // vim: tabstop=2 shiftwidth=2 expandtab
diff --git a/tests/basics/macros/print-volumes.mac b/tests/basics/macros/print-volumes.mac
index d9e9396b..2f80ae7a 100644
--- a/tests/basics/macros/print-volumes.mac
+++ b/tests/basics/macros/print-volumes.mac
@@ -1,3 +1,6 @@
+# note: this file cannot be overlap-checked on G4 with USolids.
+/RMG/Geometry/GDMLDisableOverlapCheck true
+
 /run/initialize
 
 /RMG/Geometry/PrintListOfLogicalVolumes
diff --git a/tests/basics/macros/run-2nbb.mac b/tests/basics/macros/run-2nbb.mac
index 66fac7cd..f6cf1faa 100644
--- a/tests/basics/macros/run-2nbb.mac
+++ b/tests/basics/macros/run-2nbb.mac
@@ -1,3 +1,6 @@
+# note: this file cannot be overlap-checked on G4 with USolids.
+/RMG/Geometry/GDMLDisableOverlapCheck true
+
 /run/initialize
 
 /RMG/Generator/Confine Volume