diff --git a/processgrid.m b/processgrid.m
index af3a1bcf..67ad1790 100644
--- a/processgrid.m
+++ b/processgrid.m
@@ -32,10 +32,5 @@ function varargout = processgrid(varargin)
 % $Date$
 % $Revision$
 
-% Build MEX edition of same.
-%
-buildmex CFLAGS='$CFLAGS -Wall -fPIC' processgrid.c preprocess.c ...
-         uniquepoints.c facetopology.c sparsetable.c mxgrdecl.c
-
-% Call MEX edition.
-[varargout{1:nargout}] = processgrid(varargin{:});
+[varargout{1:nargout}] = processgrid_mex(varargin{:});
+varargout{1}.griddim = 3;
diff --git a/processgrid_mex.m b/processgrid_mex.m
new file mode 100644
index 00000000..1becfb7a
--- /dev/null
+++ b/processgrid_mex.m
@@ -0,0 +1,42 @@
+function varargout = processgrid_mex(varargin)
+%Compute grid topology and geometry from pillar grid description.
+%
+% SYNOPSIS:
+%   G = processGRDECL(grdecl)
+%
+% PARAMETERS:
+%   grdecl - Raw pillar grid structure, as defined by function
+%            'readGRDECL', with fields COORDS, ZCORN and, possibly, ACTNUM.
+%
+% RETURNS:
+%   G      - Valid grid definition containing connectivity, cell
+%            geometry, face geometry and unique nodes.
+%
+% EXAMPLE:
+%   G = processgrid(readGRDECL('small.grdecl'));
+%   plotGrid(G); view(10,45);
+%
+% SEE ALSO:
+%   processGRDECL, readGRDECL, deactivateZeroPoro, removeCells.
+
+%{
+#COPYRIGHT#
+%}
+
+% $Date$
+% $Revision$
+
+% Copyright 2009 SINTEF ICT, Applied Mathematics.
+% Mex gateway by Jostein R. Natvig, SINTEF ICT.
+
+% $Date$
+% $Revision$
+
+% Build MEX edition of same.
+%
+buildmex CFLAGS='$CFLAGS -Wall -fPIC' processgrid.c preprocess.c ...
+         uniquepoints.c facetopology.c sparsetable.c mxgrdecl.c  ...
+         -output processgrid_mex.mexa64
+
+% Call MEX edition.
+[varargout{1:nargout}] = processgrid_mex(varargin{:});