diff --git a/CMakeLists.txt b/CMakeLists.txt
index 216d5bb..3fd318f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,6 +67,7 @@ target_include_directories(
 		PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/3rdparty/rbdl/include>
 		PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/glfw/deps>
 		PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/imgui>
+		PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/ImGuizmo>
 		PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/vectorial/include>
 		PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/tracy>
 )
@@ -82,6 +83,7 @@ target_sources(vissim PRIVATE
 	3rdparty/imgui/imgui_demo.cpp
 	3rdparty/imgui/backends/imgui_impl_glfw.cpp
 	3rdparty/imgui/backends/imgui_impl_opengl3.cpp
+	3rdparty/ImGuizmo/ImGuizmo.cpp
 	src/vissim.cc
 	src/sthstry.c
 	src/simulator.cc
diff --git a/include/simulator.h b/include/simulator.h
index 515d0c3..90391e7 100644
--- a/include/simulator.h
+++ b/include/simulator.h
@@ -10,6 +10,7 @@ typedef struct srcmdbuf srcmdbuf;
 
 void simulator_init();
 void simulator_reset();
+void simulator_gui();
 void simulator_update(double dt);
 void simulator_step(double dt);
 void simulator_draw(srcmdbuf* cmdbuf);
diff --git a/src/sconvcol.h b/src/sconvcol.h
index 439308c..7aa43c0 100644
--- a/src/sconvcol.h
+++ b/src/sconvcol.h
@@ -524,6 +524,7 @@ float sch_query_edge_directions (const sch_hull* hull_A, const sch_hull* hull_B,
         axis = simd4f_sub(simd4f_zero(), axis);
       }
 
+      // TODO: properly handle touching parallel edges.
       if (simd4f_get_x(simd4f_length3_squared(axis)) < SCH_EPS) {
         continue;
       }
diff --git a/src/simulator.cc b/src/simulator.cc
index 0ed02dd..99fdf76 100644
--- a/src/simulator.cc
+++ b/src/simulator.cc
@@ -115,7 +115,7 @@ void simulator_reset() {
   sSimTimeAccumulator = 0.;
 }
 
-void simulator_update(double dt) {
+void simulator_gui() {
   ZoneScoped;
 
   ImGui::Begin("Simulator");
@@ -186,6 +186,10 @@ void simulator_update(double dt) {
   }
 
   ImGui::End();
+}
+
+void simulator_update(double dt) {
+  ZoneScoped;
 
   if (!sIsPaused) {
     sSimTimeAccumulator += dt;
diff --git a/src/srender.h b/src/srender.h
index 004f334..0222ced 100644
--- a/src/srender.h
+++ b/src/srender.h
@@ -736,6 +736,8 @@ void srview_cleanup_framebuffer(srview* sv) {
 void srview_set_size(srview* sv, int width, int height) {
   if (sv->width == width && sv->height == height) {
     return;
+  } else {
+    gLog("Resizing view to %d, %d", width, height);
   }
 
   sv->width = width;
diff --git a/src/vissim.cc b/src/vissim.cc
index 849be0c..e3cc4a4 100644
--- a/src/vissim.cc
+++ b/src/vissim.cc
@@ -4,20 +4,22 @@
 // clang-format on
 
 #include <GLFW/glfw3.h>
-#include <GLFW/glfw3native.h>
-#include <X11/Xlib.h>
-#include <signal.h>
+#include <csignal>
 #include <unistd.h>
 
 #include <Tracy.hpp>
 #include <cstdio>
-#include <cstdlib>
 #include <iostream>
-#include <sstream>
 
 #include "backends/imgui_impl_glfw.h"
 #include "backends/imgui_impl_opengl3.h"
 #include "imgui.h"
+#include "ImGuizmo.h"
+
+#ifndef IMGUI_DEFINE_MATH_OPERATORS
+#define IMGUI_DEFINE_MATH_OPERATORS
+#endif
+#include "imgui_internal.h"
 #include "simulator.h"
 #include "srender.h"
 #include "utils.h"
@@ -30,9 +32,38 @@ srndr* gRndr = nullptr;
 srview* gView = nullptr;
 srcmdbuf* gRndrCmds = nullptr;
 
+simd4x4f gViewMatrix = {
+    simd4f_create(1.f, 0.f, 0.0, 0.f),
+    simd4f_create(0.f, 1.f, 0.f, 0.f),
+    simd4f_create(0.f, 0.f, 1.f, 0.f),
+    simd4f_create(0.f, 0.f, 0.f, 1.f)};
+simd4x4f gProjMatrix{
+    simd4f_create(1.f, 0.f, 0.0, 0.f),
+    simd4f_create(0.f, 1.f, 0.f, 0.f),
+    simd4f_create(0.f, 0.f, 1.f, 0.f),
+    simd4f_create(0.f, 0.f, 0.f, 1.f)};
+simd4x4f gTransformMatrix{
+    simd4f_create(1.0f, 0.f, 0.0, 0.f),
+    simd4f_create(0.f, 1.0f, 0.f, 0.f),
+    simd4f_create(0.f, 0.f, 1.0f, 0.f),
+    simd4f_create(0.f, 0.f, 0.f, 1.f)};
+
+vectorial_inline simd4x4f simd4x4f_scale(simd4f s) {
+  return simd4x4f_create(
+      simd4f_create(simd4f_get_x(s), 0.f, 0.f, 0.f),
+      simd4f_create(0.f, simd4f_get_y(s), 0.f, 0.f),
+      simd4f_create(0.f, 0.f, simd4f_get_z(s), 0.f),
+      simd4f_create(0.f, 0.f, 0.f, simd4f_get_w(s)));
+}
+
 double mouse_scroll_x = 0.;
 double mouse_scroll_y = 0.;
 
+enum ViewMode { ViewModeSimulation = 0, ViewModeGuizmoTest = 1 };
+
+ViewMode gViewMode = ViewModeSimulation;
+bool gGizmoEnabled = true;
+
 using namespace std;
 
 static void error_callback(int error, const char* description) {
@@ -146,30 +177,210 @@ void ShowDockspace(bool open) {
   ImGui::End();
 }
 
+static ImGuizmo::OPERATION mCurrentGizmoOperation(ImGuizmo::TRANSLATE);
+int gizmoCount = 1;
+float camDistance = 8.f;
+
+void RenderGuizmoTest(srcmdbuf* cmdbuf) {
+  srcmd rcmd;
+  srcmd_clear(&rcmd);
+
+  rcmd.type = SRndrCmdTypeGrid;
+  for (int i = -1; i <= 1; i++) {
+    for (int j = -1; j <= 1; j++) {
+      simd4x4f_translation(&rcmd.mat, 0.0f, 0.0f, 0.0f);
+      srcmdbuf_add(cmdbuf, &rcmd);
+    }
+  }
+
+  rcmd.type = SRndrCmdTypeCube;
+  rcmd.mat = gTransformMatrix;
+  srcmdbuf_add(cmdbuf, &rcmd);
+}
+
+void ShowViewManip() {
+  const ImGuiStyle& imgui_style = ImGui::GetStyle();
+
+  ImGuizmo::SetDrawlist();
+  float windowWidth = (float)ImGui::GetWindowWidth();
+  float windowHeight = (float)ImGui::GetWindowHeight();
+  ImGuizmo::SetRect(
+      ImGui::GetWindowPos().x,
+      ImGui::GetWindowPos().y,
+      windowWidth,
+      windowHeight);
+  float viewManipulateRight = ImGui::GetWindowPos().x + windowWidth;
+
+  int title_height = ImGui::GetFontSize() + imgui_style.FramePadding.y * 2;
+  ImVec2 window_pos = ImGui::GetWindowPos();
+
+  ImVec2 view_manip_widget_size(128, 128);
+  ImVec2 view_manip_widget_pos(
+      viewManipulateRight - 128 - imgui_style.WindowPadding.x,
+      window_pos.y + title_height + imgui_style.WindowPadding.y);
+  ImGui::SetCursorPos(view_manip_widget_pos - ImGui::GetWindowPos());
+  ImGui::InvisibleButton("ViewManipulator", view_manip_widget_size);
+  ImGuizmo::ViewManipulate(
+      (float*)&(gViewMatrix.x),
+      10.0f,
+      view_manip_widget_pos,
+      view_manip_widget_size,
+      0x40404040);
+}
+
+void ShowTransformManip(
+    float* cameraView,
+    float* cameraProjection,
+    float* matrix) {
+  static ImGuizmo::MODE mCurrentGizmoMode(ImGuizmo::LOCAL);
+  static bool useSnap = false;
+  static float snap[3] = {1.f, 1.f, 1.f};
+  static float bounds[] = {-0.5f, -0.5f, -0.5f, 0.5f, 0.5f, 0.5f};
+  static float boundsSnap[] = {0.1f, 0.1f, 0.1f};
+  static bool boundSizing = false;
+  static bool boundSizingSnap = false;
+  bool useWindow = false;
+  bool editTransformDecomposition = true;
+
+  ImVec2 window_size = ImGui::GetWindowSize();
+  ImVec2 window_pos = ImGui::GetWindowPos();
+
+  ImGuiStyle imgui_style = ImGui::GetStyle();
+  int title_height = ImGui::GetFontSize() + imgui_style.FramePadding.y * 2;
+
+  window_pos.x += imgui_style.WindowPadding.x;
+  window_pos.y += imgui_style.WindowPadding.y + title_height;
+
+  window_size.x -= imgui_style.WindowPadding.x * 2;
+  window_size.y -= imgui_style.WindowPadding.y * 2 + title_height;
+
+  ImGui::Begin("Guizmo");
+
+  if (editTransformDecomposition) {
+    if (ImGui::IsKeyPressed(90)) mCurrentGizmoOperation = ImGuizmo::TRANSLATE;
+    if (ImGui::IsKeyPressed(69)) mCurrentGizmoOperation = ImGuizmo::ROTATE;
+    if (ImGui::IsKeyPressed(82))  // r Key
+      mCurrentGizmoOperation = ImGuizmo::SCALE;
+    if (ImGui::RadioButton(
+            "Translate",
+            mCurrentGizmoOperation == ImGuizmo::TRANSLATE))
+      mCurrentGizmoOperation = ImGuizmo::TRANSLATE;
+    ImGui::SameLine();
+    if (ImGui::RadioButton(
+            "Rotate",
+            mCurrentGizmoOperation == ImGuizmo::ROTATE))
+      mCurrentGizmoOperation = ImGuizmo::ROTATE;
+    ImGui::SameLine();
+    if (ImGui::RadioButton("Scale", mCurrentGizmoOperation == ImGuizmo::SCALE))
+      mCurrentGizmoOperation = ImGuizmo::SCALE;
+    if (ImGui::RadioButton(
+            "Universal",
+            mCurrentGizmoOperation == ImGuizmo::UNIVERSAL))
+      mCurrentGizmoOperation = ImGuizmo::UNIVERSAL;
+    float matrixTranslation[3], matrixRotation[3], matrixScale[3];
+    ImGuizmo::DecomposeMatrixToComponents(
+        matrix,
+        matrixTranslation,
+        matrixRotation,
+        matrixScale);
+    ImGui::InputFloat3("Tr", matrixTranslation);
+    ImGui::InputFloat3("Rt", matrixRotation);
+    ImGui::InputFloat3("Sc", matrixScale);
+    ImGuizmo::RecomposeMatrixFromComponents(
+        matrixTranslation,
+        matrixRotation,
+        matrixScale,
+        matrix);
+
+    if (mCurrentGizmoOperation != ImGuizmo::SCALE) {
+      if (ImGui::RadioButton("Local", mCurrentGizmoMode == ImGuizmo::LOCAL))
+        mCurrentGizmoMode = ImGuizmo::LOCAL;
+      ImGui::SameLine();
+      if (ImGui::RadioButton("World", mCurrentGizmoMode == ImGuizmo::WORLD))
+        mCurrentGizmoMode = ImGuizmo::WORLD;
+    }
+    if (ImGui::IsKeyPressed(83)) useSnap = !useSnap;
+    ImGui::Checkbox("", &useSnap);
+    ImGui::SameLine();
+
+    switch (mCurrentGizmoOperation) {
+      case ImGuizmo::TRANSLATE:
+        ImGui::InputFloat3("Snap", &snap[0]);
+        break;
+      case ImGuizmo::ROTATE:
+        ImGui::InputFloat("Angle Snap", &snap[0]);
+        break;
+      case ImGuizmo::SCALE:
+        ImGui::InputFloat("Scale Snap", &snap[0]);
+        break;
+    }
+    ImGui::Checkbox("Bound Sizing", &boundSizing);
+    if (boundSizing) {
+      ImGui::PushID(3);
+      ImGui::Checkbox("", &boundSizingSnap);
+      ImGui::SameLine();
+      ImGui::InputFloat3("Snap", boundsSnap);
+      ImGui::PopID();
+    }
+  }
+
+  ImGui::End();
+
+  ImGuiIO& io = ImGui::GetIO();
+  float viewManipulateRight = io.DisplaySize.x;
+  float viewManipulateTop = 0;
+  if (useWindow) {
+    ImGui::SetNextWindowSize(ImVec2(800, 400));
+    ImGui::SetNextWindowPos(ImVec2(400, 20));
+    ImGui::PushStyleColor(
+        ImGuiCol_WindowBg,
+        (ImVec4)ImColor(0.35f, 0.3f, 0.3f));
+    ImGui::Begin("Gizmo", 0);
+    ImGuizmo::SetDrawlist();
+    float windowWidth = (float)ImGui::GetWindowWidth();
+    ImGuizmo::SetRect(window_pos.x, window_pos.y, window_size.x, window_size.y);
+  } else {
+    ImGuizmo::SetDrawlist();
+    ImGuizmo::SetRect(window_pos.x, window_pos.y, window_size.x, window_size.y);
+  }
+
+  simd4x4f identity_mat;
+  simd4x4f_identity(&identity_mat);
+
+  ImGuizmo::Manipulate(
+      cameraView,
+      cameraProjection,
+      mCurrentGizmoOperation,
+      mCurrentGizmoMode,
+      matrix,
+      NULL,
+      useSnap ? &snap[0] : NULL,
+      boundSizing ? bounds : NULL,
+      boundSizingSnap ? boundsSnap : NULL);
+
+  if (useWindow) {
+    ImGui::End();
+    ImGui::PopStyleColor(1);
+  }
+}
+
 void DoRender() {
   ZoneScoped;
 
-  // Render Output
-  ImGui::Begin("Render Output");
+  const ImGuiStyle& imgui_style = ImGui::GetStyle();
 
-  // Update the view
+  // Render Output
+  ImGui::Begin("Render Output", nullptr, ImGuiWindowFlags_NoScrollbar);
+
+  // Update the gViewMatrix
   const ImVec2 content_avail = ImGui::GetContentRegionAvail();
   srview_set_size(gView, content_avail.x, content_avail.y);
-  simd4x4f view;
-  simd4x4f proj;
-  simd4x4f_translation(&view, 0.1f, 0.1f, -0.5f);
-  simd4f eye = simd4f_create(0.f, 3.f, 10.f, 1.f);
-  simd4x4f_lookat(
-      &view,
-      eye,
-      simd4f_create(0.f, 1.f, 0.f, 1.f),
-      simd4f_create(0.f, 1.f, 0.f, 1.f));
 
   float view_width = content_avail.x / 50.f;
   float view_height = content_avail.y / 50.f;
 
   simd4x4f_ortho(
-      &proj,
+      &gProjMatrix,
       -0.5f * view_width,
       0.5f * view_width,
       -0.5f * view_height,
@@ -177,13 +388,13 @@ void DoRender() {
       -50.0f,
       50.0f);
   simd4x4f_perspective(
-      &proj,
+      &gProjMatrix,
       70.f * (M_PI / 180.f),
       view_width / view_height,
       0.1f,
       50.f);
-  srview_set_view(gView, view);
-  srview_set_proj(gView, proj);
+  srview_set_view(gView, gViewMatrix);
+  srview_set_proj(gView, gProjMatrix);
 
   // Populate render commands
   srcmdbuf_clear(gRndrCmds);
@@ -194,7 +405,12 @@ void DoRender() {
   rcmd.type = SRndrCmdTypeFrame;
   srcmdbuf_add(gRndrCmds, &rcmd);
 
-  simulator_draw(gRndrCmds);
+  if (gViewMode == ViewModeSimulation) {
+    simulator_draw(gRndrCmds);
+    simulator_gui();
+  } else {
+    RenderGuizmoTest(gRndrCmds);
+  }
 
   // Perform the actual render
   srndr_render(gRndr, gView, gRndrCmds);
@@ -207,6 +423,22 @@ void DoRender() {
       ImVec2(0.0f, 1.0f),
       ImVec2(1.0f, 0.0f));
 
+  ImGuiIO& io = ImGui::GetIO();
+
+  ShowViewManip();
+  ShowTransformManip((float*)&(gViewMatrix),
+                     (float*)&(gProjMatrix),
+                     (float*)(&gTransformMatrix));
+
+  /*
+  EditTransform(
+      (float*)&(gViewMatrix),
+      (float*)&(gProjMatrix),
+      (float*)(&gTransformMatrix),
+      true,
+      window_pos,
+      window_size);
+*/
   ImGui::End();
 }
 
@@ -249,6 +481,10 @@ int main(void) {
   std::cout << "GLSL Version  : " << glGetString(GL_SHADING_LANGUAGE_VERSION)
             << endl;
 
+  glEnable(GL_DEBUG_OUTPUT);
+  //  glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
+  glDebugMessageCallback(opengl_error_callback, nullptr);
+
   // During init, enable debug output
   //	glEnable              ( GL_DEBUG_OUTPUT );
   //	glDebugMessageCallback( (GLDEBUGPROC) opengl_error_callback, 0 );
@@ -290,6 +526,18 @@ int main(void) {
   gRndrCmds = srcmdbuf_create(1024);
   simulator_init();
 
+  simd4x4f_translation(&gViewMatrix, 0.1f, 0.1f, -0.5f);
+  simd4f eye = simd4f_create(0.f, 3.f, 10.f, 1.f);
+
+  simd4x4f_lookat(
+      &gViewMatrix,
+      eye,
+      simd4f_create(0.f, 0.f, 0.f, 1.f),
+      simd4f_create(0.f, 1.f, 0.f, 1.f));
+
+  simd4x4f scale_mat = simd4x4f_scale(simd4f_create(1.f, 1.f, 1.f, 1.f));
+  simd4x4f_mul(&gTransformMatrix, &scale_mat, &gTransformMatrix);
+
   while (!glfwWindowShouldClose(gWindow)) {
     FrameMark;
     frame_counter++;
@@ -307,6 +555,8 @@ int main(void) {
       ImGui_ImplOpenGL3_NewFrame();
       ImGui_ImplGlfw_NewFrame();
       ImGui::NewFrame();
+      ImGuizmo::BeginFrame();
+      ImGuizmo::Enable(gGizmoEnabled);
     }
 
     frame_time_last = frame_time_current;