diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..ab0ee4729
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+# Build directories
+build*/
\ No newline at end of file
diff --git a/src/rocky/vsg/ecs/WidgetSystem.cpp b/src/rocky/vsg/ecs/WidgetSystem.cpp
index 63f3b73b5..17e3a2094 100644
--- a/src/rocky/vsg/ecs/WidgetSystem.cpp
+++ b/src/rocky/vsg/ecs/WidgetSystem.cpp
@@ -13,7 +13,10 @@
 #include <rocky/Rendering.h>
 #include <rocky/ecs/Widget.h>
 #include <rocky/ecs/Visibility.h>
+
+#ifdef ROCKY_HAS_IMGUI
 #include <imgui.h>
+#endif
 
 using namespace ROCKY_NAMESPACE;
 
@@ -59,6 +62,7 @@ WidgetSystemNode::WidgetSystemNode(Registry& in_registry) :
 void
 WidgetSystemNode::initialize(VSGContext& context)
 {
+#ifdef ROCKY_HAS_IMGUI
     // register me as a gui rendering callback.
     auto recorder = [this](detail::RenderingState& rs, void* imguiContext)
         {
@@ -114,6 +118,7 @@ WidgetSystemNode::initialize(VSGContext& context)
         };
 
     context->guiRecorders.emplace_back(recorder);
+#endif // ROCKY_HAS_IMGUI
 }
 
 void
diff --git a/src/rocky/vsg/imgui/ImGuiIntegration.h b/src/rocky/vsg/imgui/ImGuiIntegration.h
index 817b73cb8..388826188 100644
--- a/src/rocky/vsg/imgui/ImGuiIntegration.h
+++ b/src/rocky/vsg/imgui/ImGuiIntegration.h
@@ -9,6 +9,8 @@
 #include <rocky/Callbacks.h>
 #include <rocky/vsg/imgui/SendEventsToImGui.h>
 #include <rocky/vsg/imgui/RenderImGui.h>
+
+#ifdef ROCKY_HAS_IMGUI
 #include <imgui.h>
 
 /**
@@ -162,3 +164,5 @@ namespace ROCKY_NAMESPACE
         };
     }
 }
+
+#endif // ROCKY_HAS_IMGUI
diff --git a/src/rocky/vsg/imgui/RenderImGui.h b/src/rocky/vsg/imgui/RenderImGui.h
index 04718bd6b..b520d6824 100644
--- a/src/rocky/vsg/imgui/RenderImGui.h
+++ b/src/rocky/vsg/imgui/RenderImGui.h
@@ -24,6 +24,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 </editor-fold> */
 #include <rocky/vsg/Common.h>
 
+#ifdef ROCKY_HAS_IMGUI
 #include <imgui.h>
 #include <functional>
 
@@ -98,3 +99,5 @@ namespace ROCKY_NAMESPACE
     // temporary workaround for Dear ImGui's nonexistent sRGB awareness
     //extern void ImGuiStyle_sRGB_to_linear(ImGuiStyle& style);
 }
+
+#endif // ROCKY_HAS_IMGUI
diff --git a/src/rocky/vsg/imgui/SendEventsToImGui.cpp b/src/rocky/vsg/imgui/SendEventsToImGui.cpp
index d9a328fa6..da1b7537a 100644
--- a/src/rocky/vsg/imgui/SendEventsToImGui.cpp
+++ b/src/rocky/vsg/imgui/SendEventsToImGui.cpp
@@ -22,6 +22,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 </editor-fold> */
 
 #include "SendEventsToImGui.h"
+
+#ifdef ROCKY_HAS_IMGUI
 #include <imgui.h>
 
 #include <vsg/ui/KeyEvent.h>
@@ -309,4 +311,6 @@ void SendEventsToImGui::apply(vsg::FrameEvent& /*frame*/)
     io.DeltaTime = std::chrono::duration_cast<std::chrono::duration<float>>(t1 - t0).count();
 
     t0 = t1;
-}
\ No newline at end of file
+}
+
+#endif // ROCKY_HAS_IMGUI
\ No newline at end of file
diff --git a/src/rocky/vsg/imgui/SendEventsToImGui.h b/src/rocky/vsg/imgui/SendEventsToImGui.h
index 466884aa9..fdffec6d1 100644
--- a/src/rocky/vsg/imgui/SendEventsToImGui.h
+++ b/src/rocky/vsg/imgui/SendEventsToImGui.h
@@ -27,6 +27,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <chrono>
 #include <vsg/core/Visitor.h>
 #include <vsg/ui/KeyEvent.h>
+
+#ifdef ROCKY_HAS_IMGUI
 #include <imgui.h>
 
 namespace ROCKY_NAMESPACE
@@ -59,3 +61,5 @@ namespace ROCKY_NAMESPACE
     };
 }
 
+#endif // ROCKY_HAS_IMGUI
+