diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d508c8..dc1e7c1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -48,6 +48,7 @@ qt_add_executable(${AppExec}
     src/Engine/Operator/Geometry.cpp
     src/Engine/Operator/GeometryOperator.cpp
     src/Engine/Operator/GeometryConnection.cpp
+    src/Engine/Operator/GeometryOpDef.cpp
     src/Engine/Network/NetworkManager.cpp
 )
 
@@ -65,6 +66,7 @@ add_executable(${TestExec}
     src/Engine/Operator/GeometryOperator.cpp
     src/Engine/Network/NetworkManager.cpp
     src/Engine/Operator/GeometryConnection.cpp
+    src/Engine/Operator/GeometryOpDef.cpp
 )
 find_package(Catch2 3 REQUIRED)
 target_link_libraries(${TestExec} PRIVATE Catch2::Catch2WithMain Eigen3::Eigen Qt6::Core )
diff --git a/src/Engine/Network/NetworkManager.cpp b/src/Engine/Network/NetworkManager.cpp
index 8e41ecb..83b134d 100644
--- a/src/Engine/Network/NetworkManager.cpp
+++ b/src/Engine/Network/NetworkManager.cpp
@@ -75,6 +75,7 @@ void enzo::nt::NetworkManager::setDisplayOp(OpId opId)
 
     // --------
 
+    std::cout << "size: " << dependencyGraph.size() << "\n";
     for(enzo::nt::OpId opId : dependencyGraph)
     {
         prevGeometry = cookOp(opId, prevGeometry);
@@ -86,7 +87,9 @@ enzo::geo::Geometry enzo::nt::NetworkManager::cookOp(enzo::nt::OpId opId, enzo::
 {
     std::shared_ptr<ga::Attribute> PAttr = inputGeometry.getAttribByName(ga::AttrOwner::POINT, "P");
     ga::AttributeHandleVector3 PAttrHandle = ga::AttributeHandleVector3(PAttr);
-    
+
+    enzo::nt::GeometryOperator& op = getGeoOperator(opId);
+    op.cookOp();
 
     for(int i=0; i<PAttrHandle.getAllValues().size(); ++i)
     {
diff --git a/src/Engine/Operator/GeometryOpDef.cpp b/src/Engine/Operator/GeometryOpDef.cpp
new file mode 100644
index 0000000..31546b7
--- /dev/null
+++ b/src/Engine/Operator/GeometryOpDef.cpp
@@ -0,0 +1,63 @@
+#include "Engine/Operator/GeometryOpDef.h"
+#include <stdexcept>
+#include <iostream>
+
+bool enzo::nt::GeometryOpDef::outputRequested(unsigned int outputIndex)
+{
+    // TODO: implement
+    return true;
+}
+
+const enzo::geo::Geometry& enzo::nt::GeometryOpDef::getInputGeoView(unsigned int inputIndex)
+{
+    // TODO: implement
+    return enzo::geo::Geometry();
+
+}
+
+enzo::geo::Geometry enzo::nt::GeometryOpDef::cloneInputGeo(unsigned int inputIndex)
+{
+    // TODO: implement
+    return enzo::geo::Geometry();
+}
+
+void enzo::nt::GeometryOpDef::setOutputGeometry(unsigned int outputIndex, enzo::geo::Geometry geometry)
+{
+    if(outputIndex>maxOutputs_)
+    {
+        throw std::runtime_error("Cannot set output geometry to index > maxOutputs");
+    }
+    outputGeometry_[outputIndex] = geometry;
+}
+
+enzo::nt::GeometryOpDef::GeometryOpDef()
+{
+    minInputs_=1;
+    maxInputs_=4;
+    maxOutputs_=4;
+    outputGeometry_ = std::vector<enzo::geo::Geometry>(4, enzo::geo::Geometry());
+}
+
+void enzo::nt::GeometryOpDef::cookOp()
+{
+    using namespace enzo;
+    std::cout << "COOKING\n";
+
+    if(outputRequested(0))
+    {
+        // copy input geometry
+        geo::Geometry geo = cloneInputGeo(0);
+
+        // set output geometry
+        setOutputGeometry(0, geo);
+    }
+
+    // if(outputRequested(1))
+    // {
+    //     // create new geometry
+    //     const geo::Geometry& geo1 = getInputGeoView(0);
+    //     geo::Geometry geo2;
+
+    //     setOutputGeometry(1, geo2);
+    // }
+}
diff --git a/src/Engine/Operator/GeometryOpDef.h b/src/Engine/Operator/GeometryOpDef.h
new file mode 100644
index 0000000..e8c40b4
--- /dev/null
+++ b/src/Engine/Operator/GeometryOpDef.h
@@ -0,0 +1,23 @@
+#pragma once
+#include "Engine/Operator/Geometry.h"
+
+namespace enzo::nt
+{
+class GeometryOpDef
+{
+public:
+    GeometryOpDef();
+    void cookOp();
+private:
+    std::vector<enzo::geo::Geometry> outputGeometry_;
+    unsigned int minInputs_;
+    unsigned int maxInputs_;
+    unsigned int maxOutputs_;
+protected:
+    const enzo::geo::Geometry& getInputGeoView(unsigned int inputIndex);
+    enzo::geo::Geometry cloneInputGeo(unsigned int inputIndex);
+    bool outputRequested(unsigned int outputIndex);
+    
+    void setOutputGeometry(unsigned int outputIndex, enzo::geo::Geometry geometry);
+};
+}
diff --git a/src/Engine/Operator/GeometryOperator.cpp b/src/Engine/Operator/GeometryOperator.cpp
index bcbf953..3e04907 100644
--- a/src/Engine/Operator/GeometryOperator.cpp
+++ b/src/Engine/Operator/GeometryOperator.cpp
@@ -28,8 +28,13 @@ nt::GeometryOperator::GeometryOperator()
     // TODO: drive by geometry definition
     maxInputs_=4;
     maxOutputs_=4;
+    opDef_ = new enzo::nt::GeometryOpDef();
 }
 
+void enzo::nt::GeometryOperator::cookOp()
+{
+    opDef_->cookOp();
+}
 
 void nt::GeometryOperator::addInputConnection(std::shared_ptr<nt::GeometryConnection> connection)
 {
diff --git a/src/Engine/Operator/GeometryOperator.h b/src/Engine/Operator/GeometryOperator.h
index 0a5f8ca..18d0b95 100644
--- a/src/Engine/Operator/GeometryOperator.h
+++ b/src/Engine/Operator/GeometryOperator.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "Engine/Operator/GeometryConnection.h"
+#include "Engine/Operator/GeometryOpDef.h"
 #include "Engine/Types.h"
 #include <optional>
 #include <memory>
@@ -16,6 +17,8 @@ public:
     GeometryOperator(const GeometryOperator&)            = delete;
     GeometryOperator& operator=(const GeometryOperator&) = delete;
 
+    void cookOp();
+
     void addInputConnection(std::shared_ptr<nt::GeometryConnection> connection);
     void addOutputConnection(std::shared_ptr<nt::GeometryConnection> connection);
     std::vector<std::shared_ptr<const GeometryConnection>> getInputConnections() const;
@@ -33,6 +36,6 @@ private:
     std::vector<std::shared_ptr<nt::GeometryConnection>> outputConnections_;
     unsigned int maxInputs_;
     unsigned int maxOutputs_;
-
+    enzo::nt::GeometryOpDef* opDef_;
 };
 }