diff --git a/src/Engine/Network/NetworkManager.cpp b/src/Engine/Network/NetworkManager.cpp
index 345aa40..ac36091 100644
--- a/src/Engine/Network/NetworkManager.cpp
+++ b/src/Engine/Network/NetworkManager.cpp
@@ -15,7 +15,7 @@ enzo::nt::OpId enzo::nt::NetworkManager::addOperator()
 {
 
     maxOpId_++;
-    gopStore_.emplace(maxOpId_, std::make_unique<GeometryOperator>(maxOpId_, std::make_unique<GOP_test>(maxOpId_)));
+    gopStore_.emplace(maxOpId_, std::make_unique<GeometryOperator>(maxOpId_, &GOP_test::ctor));
     std::cout << "adding operator " << maxOpId_ << "\n";
 
     return maxOpId_;
diff --git a/src/Engine/Operator/GOP_test.h b/src/Engine/Operator/GOP_test.h
index 17e4ca2..db8e8ac 100644
--- a/src/Engine/Operator/GOP_test.h
+++ b/src/Engine/Operator/GOP_test.h
@@ -7,5 +7,9 @@ class GOP_test
 public:
     GOP_test(enzo::nt::OpId opId);
     virtual void cookOp();
+    static enzo::nt::GeometryOpDef* ctor(enzo::nt::OpId opId)
+    {
+        return new GOP_test(opId);
+    }
 
 };
diff --git a/src/Engine/Operator/GeometryOperator.cpp b/src/Engine/Operator/GeometryOperator.cpp
index 4f45d54..350eb5d 100644
--- a/src/Engine/Operator/GeometryOperator.cpp
+++ b/src/Engine/Operator/GeometryOperator.cpp
@@ -21,8 +21,8 @@ void enzo::nt::connectOperators(enzo::nt::OpId inputOpId, unsigned int inputInde
     outputOp.addInputConnection(newConnection);
 }
 
-nt::GeometryOperator::GeometryOperator(enzo::nt::OpId opId, std::unique_ptr<enzo::nt::GeometryOpDef> opDef)
-: opId_{opId}, opDef_(std::move(opDef))
+nt::GeometryOperator::GeometryOperator(enzo::nt::OpId opId, enzo::nt::GeometryOpDef* (*ctorFunc)(enzo::nt::OpId))
+: opId_{opId}, opDef_(ctorFunc(opId))
 {
     // TODO: drive by geometry definition
     maxInputs_=4;
diff --git a/src/Engine/Operator/GeometryOperator.h b/src/Engine/Operator/GeometryOperator.h
index c605a24..64ee13c 100644
--- a/src/Engine/Operator/GeometryOperator.h
+++ b/src/Engine/Operator/GeometryOperator.h
@@ -11,7 +11,7 @@ void connectOperators(enzo::nt::OpId inputOpId, unsigned int inputIndex, enzo::n
 class GeometryOperator
 {
 public:
-    GeometryOperator(enzo::nt::OpId opId, std::unique_ptr<enzo::nt::GeometryOpDef> opDef);
+    GeometryOperator(enzo::nt::OpId opId, enzo::nt::GeometryOpDef* (*ctorFunc)(enzo::nt::OpId));
 
     // disable copying
     GeometryOperator(const GeometryOperator&)            = delete;