diff --git a/src/Application/ProjectionMappingState.cpp b/src/Application/ProjectionMappingState.cpp
index 168ac4d..e78994c 100644
--- a/src/Application/ProjectionMappingState.cpp
+++ b/src/Application/ProjectionMappingState.cpp
@@ -272,6 +272,22 @@ void ProjectionMappingState::onKeyPressed(Application * app, ofKeyEventArgs & ar
 		 }
 		 break;
 		 
+	 case '+': // Scale surface up
+		 if(app->getSurfaceManager()->getSelectedSurface() != 0){
+			app->getCmdManager()->exec(
+				new ScaleSurfaceUpCmd(
+					app->getSurfaceManager()->getSelectedSurface(), 0.1f));
+		 }
+		 break;
+
+	 case '-': // Scale surface down
+		 if(app->getSurfaceManager()->getSelectedSurface() != 0){
+			app->getCmdManager()->exec(
+				new ScaleSurfaceDnCmd(
+					app->getSurfaceManager()->getSelectedSurface(), 0.1f));
+		 }
+		 break;
+		 
 	 default:
 		 break;
 	}
diff --git a/src/Application/ProjectionMappingState.h b/src/Application/ProjectionMappingState.h
index c01ac74..83e5684 100644
--- a/src/Application/ProjectionMappingState.h
+++ b/src/Application/ProjectionMappingState.h
@@ -25,6 +25,8 @@
 #include "ToggleAnimatedSourceCmd.h"
 #include "MvLayerUpCmd.h"
 #include "MvLayerDnCmd.h"
+#include "ScaleSurfaceUpCmd.h"
+#include "ScaleSurfaceDnCmd.h"
 #include "SurfaceType.h"
 #include "Gui.h"