diff --git a/CMakeLists.txt b/CMakeLists.txt
index dcc8e65..67024f3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,6 +29,7 @@ add_subdirectory(external/glfw)
 add_subdirectory(external/gl3w)
 add_subdirectory(external/fmt)
 
+include_directories(external/sobol)
 include_directories(external/pybind11/include)
 include_directories(external/linalg)
 include_directories(external/cereal/include)
diff --git a/src/core/samplers/sobolmat.hpp b/external/sobol/sobolmat.hpp
similarity index 100%
rename from src/core/samplers/sobolmat.hpp
rename to external/sobol/sobolmat.hpp
diff --git a/src/api/graph.h b/src/api/graph.h
index 9f9a3d7..ef0b6fb 100644
--- a/src/api/graph.h
+++ b/src/api/graph.h
@@ -27,6 +27,7 @@
 #include <api/camera.h>
 #include <api/entity.hpp>
 #include <api/integrator.h>
+#include <api/property.hpp>
 #include <api/sampler.h>
 #include <api/scene.h>
 #include <api/serialize.hpp>
@@ -47,6 +48,8 @@ namespace miyuki::core {
 
         MYK_AUTO_INIT(camera, sampler, integrator, shapes, filmDimension)
 
+        MYK_PROP(camera, sampler, integrator)
+
         MYK_DECL_CLASS(SceneGraph, "SceneGraph")
 
         void render(const std::string &outImageFile);
diff --git a/src/api/property.hpp b/src/api/property.hpp
index 4967479..3642bb2 100644
--- a/src/api/property.hpp
+++ b/src/api/property.hpp
@@ -53,7 +53,10 @@ namespace miyuki {
     } // namespace detail
     using IntProperty = detail::BasicProperty<int>;
     using FloatProperty = detail::BasicProperty<float>;
-    using Vec3fProperty = detail::BasicProperty<Vec3f>;
+    using Float3Property = detail::BasicProperty<Vec3f>;
+    using Float2Property = detail::BasicProperty<Point2f>;
+    using Int2Property = detail::BasicProperty<Point2i>;
+
     using EntityProperty = detail::BasicProperty<std::shared_ptr<Entity>>;
     // using VectorProperty = detail::BasicProperty<std::vector<std::shared_ptr<Entity>>>;
     using FileProperty = detail::BasicProperty<fs::path>;
@@ -63,14 +66,16 @@ namespace miyuki {
         virtual void visit(Property *prop) { prop->accept(this); }
         virtual void visit(IntProperty *) = 0;
         virtual void visit(FloatProperty *) = 0;
-        virtual void visit(Vec3fProperty *) = 0;
+        virtual void visit(Float3Property *) = 0;
         virtual void visit(EntityProperty *) = 0;
         virtual void visit(FileProperty *) = 0;
+        virtual void visit(Int2Property *) = 0;
+        virtual void visit(Float2Property *) = 0;
     };
 
     struct ReflPropertyVisitor {
         PropertyVisitor *visitor;
-
+        ReflPropertyVisitor(PropertyVisitor *visitor) : visitor(visitor) {}
         void visit(int &v, const char *name) {
             IntProperty prop(name, v);
             prop.accept(visitor);
@@ -82,14 +87,26 @@ namespace miyuki {
         }
 
         void visit(Vec3f &v, const char *name) {
-            Vec3fProperty prop(name, v);
+            Float3Property prop(name, v);
+            prop.accept(visitor);
+        }
+
+        void visit(Point2f &v, const char *name) {
+            Float2Property prop(name, v);
+            prop.accept(visitor);
+        }
+
+        void visit(Point2i &v, const char *name) {
+            Int2Property prop(name, v);
             prop.accept(visitor);
         }
 
         template <class T>
         std::enable_if_t<std::is_base_of_v<Entity, T>, void> visit(std::shared_ptr<T> &v, const char *name) {
-            EntityProperty prop(name, v);
+            std::shared_ptr<Entity> p = v;
+            EntityProperty prop(name, p);
             prop.accept(visitor);
+            v = std::dynamic_pointer_cast<T>(p);
         }
     };
 #define MYK_PROP(...)                                                                                                  \
diff --git a/src/core/samplers/sobol-sampler.cpp b/src/core/samplers/sobol-sampler.cpp
index 7ef2f06..baf27fa 100644
--- a/src/core/samplers/sobol-sampler.cpp
+++ b/src/core/samplers/sobol-sampler.cpp
@@ -23,7 +23,7 @@
 
 #include <api/rng.h>
 #include "sobol-sampler.h"
-#include "sobolmat.hpp"
+#include <sobolmat.hpp>
 
 
 namespace miyuki::core {
diff --git a/src/ui/ui.cpp b/src/ui/ui.cpp
index e19aa3e..015e98b 100644
--- a/src/ui/ui.cpp
+++ b/src/ui/ui.cpp
@@ -21,9 +21,9 @@
 // SOFTWARE.
 
 #include <api/graph.h>
+#include <api/log.hpp>
 #include <api/property.hpp>
 #include <api/ui/ui.h>
-#include <api/log.hpp>
 
 #ifndef NOMINMAX
 #define NOMINMAX
@@ -169,11 +169,85 @@ namespace miyuki::ui {
 
         ImGui::End();
     }
-    class MainWindow : public AbstractMainWindow, public PropertyVisitor {
+
+    class InspectorPropertyVisitor : public PropertyVisitor {
+      public:
+        // Inherited via PropertyVisitor
+        virtual void visit(IntProperty *prop) override {
+            auto value = prop->getConstRef();
+            if (ImGui::InputInt(prop->name(), &value, 1, 100, ImGuiInputTextFlags_EnterReturnsTrue)) {
+                prop->getRef() = value;
+            }
+        }
+
+        virtual void visit(FloatProperty *prop) override {
+            auto value = prop->getConstRef();
+            if (ImGui::InputFloat(prop->name(), &value, 0.0f, 0.0f, "%.3f", ImGuiInputTextFlags_EnterReturnsTrue)) {
+                prop->getRef() = value;
+            }
+        }
+
+        virtual void visit(Float3Property *prop) override {
+            auto value = prop->getConstRef();
+            if (ImGui::InputFloat3(prop->name(), (float *)&value, "%.3f", ImGuiInputTextFlags_EnterReturnsTrue)) {
+                prop->getRef() = value;
+            }
+        }
+
+        virtual void visit(EntityProperty *prop) override {
+            if (ImGui::TreeNodeEx(prop->name(), ImGuiTreeNodeFlags_DefaultOpen)) {
+                ImGui::PushID(prop->name());
+
+                if (prop->getConstRef()) {
+                    prop->getRef()->accept(this);
+                }
+                ImGui::TreePop();
+
+                ImGui::PopID();
+            }
+        }
+        virtual void visit(FileProperty *prop) override {
+            ImGui::PushID(prop->name());
+            if (ImGui::Button("select")) {
+                auto filename = GetOpenFileNameWithDialog(nullptr);
+                if (!filename.empty()) {
+                    prop->getRef() = fs::path(filename);
+                }
+            }
+            ImGui::PopID();
+        }
+    };
+
+    class ExplorerPropertyVisitor : public PropertyVisitor {
+      public:
+        // Inherited via PropertyVisitor
+        virtual void visit(IntProperty *) override {}
+        virtual void visit(FloatProperty *) override {}
+        virtual void visit(Float3Property *) override {}
+        virtual void visit(EntityProperty *prop) override {
+            if (ImGui::TreeNodeEx(prop->name(), ImGuiTreeNodeFlags_DefaultOpen)) {
+                ImGui::PushID(prop->name());
+
+                if (prop->getConstRef()) {
+                    prop->getRef()->accept(this);
+                }
+                ImGui::TreePop();
+
+                ImGui::PopID();
+            }
+        }
+        virtual void visit(FileProperty *) override {}
+        virtual void visit(Int2Property *) override {}
+        virtual void visit(Float2Property *) override {}
+    };
+    class MainWindow : public AbstractMainWindow {
         std::shared_ptr<core::SceneGraph> graph;
         void showExplorer() {
             if (ImGui::Begin("Explorer")) {
-
+                if (graph) {
+                    ExplorerPropertyVisitor visitor;
+                    graph->accept(&visitor);
+                }
                 ImGui::End();
             }
         }
@@ -223,50 +297,6 @@ namespace miyuki::ui {
             showExplorer();
             showInspector();
         }
-
-        // Inherited via PropertyVisitor
-        virtual void visit(IntProperty *prop) override {
-            auto value = prop->getConstRef();
-            if (ImGui::InputInt(prop->name(), &value, 1, 100, ImGuiInputTextFlags_EnterReturnsTrue)) {
-                prop->getRef() = value;
-            }
-        }
-
-        virtual void visit(FloatProperty *prop) override {
-            auto value = prop->getConstRef();
-            if (ImGui::InputFloat(prop->name(), &value, 0.0f, 0.0f, "%.3f", ImGuiInputTextFlags_EnterReturnsTrue)) {
-                prop->getRef() = value;
-            }
-        }
-
-        virtual void visit(Vec3fProperty *prop) override {
-            auto value = prop->getConstRef();
-            if (ImGui::InputFloat3(prop->name(), (float *)&value, "%.3f", ImGuiInputTextFlags_EnterReturnsTrue)) {
-                prop->getRef() = value;
-            }
-        }
-
-        virtual void visit(EntityProperty *prop) override {
-            if (ImGui::TreeNodeEx(prop->name(), ImGuiTreeNodeFlags_DefaultOpen)) {
-                ImGui::PushID(prop->name());
-
-                if (prop->getConstRef()) {
-                    prop->getRef()->accept(this);
-                }
-
-                ImGui::PopID();
-            }
-        }
-        virtual void visit(FileProperty *prop) override {
-            ImGui::PushID(prop->name());
-            if (ImGui::Button("select")) {
-                auto filename = GetOpenFileNameWithDialog(nullptr);
-                if (!filename.empty()) {
-                    prop->getRef() = fs::path(filename);
-                }
-            }
-            ImGui::PopID();
-        }
     };
 
     std::shared_ptr<AbstractMainWindow> MakeMainWindow(int width, int height, const std::string &title) {