diff --git a/matrices.yyp b/matrices.yyp
index 5b5dc93..27c624e 100644
--- a/matrices.yyp
+++ b/matrices.yyp
@@ -21,6 +21,7 @@
     {"id":{"name":"UggPlane","path":"scripts/UggPlane/UggPlane.yy",},"order":5,},
     {"id":{"name":"MatrixString","path":"scripts/MatrixString/MatrixString.yy",},"order":11,},
     {"id":{"name":"__UggPrebuildCylinder","path":"scripts/__UggPrebuildCylinder/__UggPrebuildCylinder.yy",},"order":3,},
+    {"id":{"name":"ScreenspaceToWorldspace","path":"scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.yy",},"order":4,},
     {"id":{"name":"__UggPrebuildSphere","path":"scripts/__UggPrebuildSphere/__UggPrebuildSphere.yy",},"order":4,},
     {"id":{"name":"MatrixTransformVertexExt","path":"scripts/MatrixTransformVertexExt/MatrixTransformVertexExt.yy",},"order":12,},
     {"id":{"name":"MatrixTranslate","path":"scripts/MatrixTranslate/MatrixTranslate.yy",},"order":13,},
@@ -28,6 +29,7 @@
     {"id":{"name":"UggTriangle","path":"scripts/UggTriangle/UggTriangle.yy",},"order":9,},
     {"id":{"name":"__UggPrebuildAABB","path":"scripts/__UggPrebuildAABB/__UggPrebuildAABB.yy",},"order":2,},
     {"id":{"name":"__shdUgg","path":"shaders/__shdUgg/__shdUgg.yy",},"order":0,},
+    {"id":{"name":"MouseToWorldspace","path":"scripts/MouseToWorldspace/MouseToWorldspace.yy",},"order":5,},
     {"id":{"name":"MatrixFlipX","path":"scripts/MatrixFlipX/MatrixFlipX.yy",},"order":3,},
     {"id":{"name":"UggRay","path":"scripts/UggRay/UggRay.yy",},"order":7,},
     {"id":{"name":"MatrixFlipY","path":"scripts/MatrixFlipY/MatrixFlipY.yy",},"order":4,},
diff --git a/scripts/MouseToWorldspace/MouseToWorldspace.gml b/scripts/MouseToWorldspace/MouseToWorldspace.gml
new file mode 100644
index 0000000..0084d34
--- /dev/null
+++ b/scripts/MouseToWorldspace/MouseToWorldspace.gml
@@ -0,0 +1,13 @@
+/// Returns the point in worldspace on the far clipping plane that lies under the mouse
+/// 
+/// @param [viewMatrix]        View matrix to use. If not provided, the current view matrix will be used
+/// @param [projectionMatrix]  Projection matrix to use. If not provided, the current projection matrix will be used
+
+function MouseToWorldspace(_viewMatrix = matrix_get(matrix_view), _projectionMatrix = matrix_get(matrix_projection))
+{
+    return ScreenspaceToWorldspace(window_mouse_get_x(),
+                                       window_get_height() - window_mouse_get_y(), //GM's coordinate system requires that we invert this axis
+                                       window_get_width(),
+                                       window_get_height(),
+                                       MatrixInverse(matrix_multiply(_viewMatrix, _projectionMatrix)));
+}
\ No newline at end of file
diff --git a/scripts/MouseToWorldspace/MouseToWorldspace.yy b/scripts/MouseToWorldspace/MouseToWorldspace.yy
new file mode 100644
index 0000000..8a0c931
--- /dev/null
+++ b/scripts/MouseToWorldspace/MouseToWorldspace.yy
@@ -0,0 +1,11 @@
+{
+  "resourceType": "GMScript",
+  "resourceVersion": "1.0",
+  "name": "MouseToWorldspace",
+  "isDnD": false,
+  "isCompatibility": false,
+  "parent": {
+    "name": "Matrices",
+    "path": "Matrices.yyp",
+  },
+}
\ No newline at end of file
diff --git a/scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.gml b/scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.gml
new file mode 100644
index 0000000..32f6576
--- /dev/null
+++ b/scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.gml
@@ -0,0 +1,35 @@
+/// Returns the point in worldspace on the far clipping plane that lies under the given screenspace coordinates
+/// 
+/// @param x                               x-coordinate in screenspace
+/// @param y                               y-coordinate in screenspace
+/// @param [width]                         Width of the screenspace render target. If not provided, the width of th current render target (either a surface or the backbuffer) will be used
+/// @param [height]                        Height of the screenspace render target. If not provided, the height of the current render target (either a surface or the backbuffer) will be used
+/// @param [inverseViewProjectionMatrix]   The inverse of the view*projection matrix. If not provided, the current view and projection matrix will be used
+
+function ScreenspaceToWorldspace(_x, _y, _width, _height, _inverseMatrix)
+{
+    if ((_width == undefined) || (_height == undefined))
+    {
+        var _surface = surface_get_target();
+    }
+    
+    if (_width  == undefined) _width  = (_surface < 0)? display_get_gui_width()  : surface_get_width( _surface);
+    if (_height == undefined) _height = (_surface < 0)? display_get_gui_height() : surface_get_height(_surface);
+    
+    _x = -1 + 2*_x/_width;
+    _y = -1 + 2*_y/_height;
+    
+    if (_inverseMatrix == undefined)
+    {
+        _inverseMatrix = MatrixInverse(matrix_multiply(matrix_get(matrix_view), matrix_get(matrix_projection)));
+    }
+    
+    var _vector = MatrixTransformVertexExt(_inverseMatrix, _x, _y, 1.0, 1.0);
+    
+    var _inverseW = 1/_vector[3];
+    _vector[@ 0] *= _inverseW;
+    _vector[@ 1] *= _inverseW;
+    _vector[@ 2] *= _inverseW;
+    
+    return _vector;
+}
\ No newline at end of file
diff --git a/scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.yy b/scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.yy
new file mode 100644
index 0000000..4c15425
--- /dev/null
+++ b/scripts/ScreenspaceToWorldspace/ScreenspaceToWorldspace.yy
@@ -0,0 +1,11 @@
+{
+  "resourceType": "GMScript",
+  "resourceVersion": "1.0",
+  "name": "ScreenspaceToWorldspace",
+  "isDnD": false,
+  "isCompatibility": false,
+  "parent": {
+    "name": "Matrices",
+    "path": "Matrices.yyp",
+  },
+}
\ No newline at end of file