diff --git a/pkgs/applications/misc/cura/default.nix b/pkgs/applications/misc/cura/default.nix
index a711cc1db87c..a53b001b0e98 100644
--- a/pkgs/applications/misc/cura/default.nix
+++ b/pkgs/applications/misc/cura/default.nix
@@ -31,6 +31,8 @@ stdenv.mkDerivation rec {
 
   configurePhase = "";
   buildPhase = "";
+  
+  patches = [ ./numpy-cast.patch ];
 
   installPhase = ''
     # Install Python code.
diff --git a/pkgs/applications/misc/cura/numpy-cast.patch b/pkgs/applications/misc/cura/numpy-cast.patch
new file mode 100644
index 000000000000..efb14182b3e6
--- /dev/null
+++ b/pkgs/applications/misc/cura/numpy-cast.patch
@@ -0,0 +1,12 @@
+diff -urN Cura-15.04.old/Cura/util/sliceEngine.py Cura-15.04/Cura/util/sliceEngine.py
+--- Cura-15.04.old/Cura/util/sliceEngine.py	2016-05-07 20:34:17.305020334 +0200
++++ Cura-15.04/Cura/util/sliceEngine.py	2016-05-07 20:40:02.993286467 +0200
+@@ -343,7 +343,7 @@
+ 						objMax[1] = max(oMax[1], objMax[1])
+ 			if objMin is None:
+ 				return
+-			pos += (objMin + objMax) / 2.0 * 1000
++			pos = numpy.add( pos, (objMin + objMax) / 2.0 * 1000, out=pos, casting='unsafe')
+ 			commandList += ['-s', 'posx=%d' % int(pos[0]), '-s', 'posy=%d' % int(pos[1])]
+ 
+ 			vertexTotal = [0] * 4