Index: /issm/trunk-jpl/src/m/classes/inversion.m
===================================================================
--- /issm/trunk-jpl/src/m/classes/inversion.m	(revision 18215)
+++ /issm/trunk-jpl/src/m/classes/inversion.m	(revision 18216)
@@ -206,5 +206,11 @@
 			WriteData(fid,'object',obj,'fieldname','vy_obs','format','DoubleMat','mattype',1,'scale',1./yts);
 			WriteData(fid,'object',obj,'fieldname','vz_obs','format','DoubleMat','mattype',1,'scale',1./yts);
-			WriteData(fid,'object',obj,'fieldname','thickness_obs','format','DoubleMat','mattype',1);
+			if(numel(obj.thickness_obs)==md.mesh.numberofelements),
+				mattype=2;
+			else
+				mattype=1;
+			end
+			WriteData(fid,'object',obj,'class','inversion','fieldname','thickness_obs','format','DoubleMat','mattype',mattype);
+
 
 			%process control parameters
Index: /issm/trunk-jpl/src/m/classes/model.m
===================================================================
--- /issm/trunk-jpl/src/m/classes/model.m	(revision 18215)
+++ /issm/trunk-jpl/src/m/classes/model.m	(revision 18216)
@@ -552,6 +552,6 @@
 			%
 			%   Example:
-			%      md=extrude(md,8,3);
-			%      md=extrude(md,8,3,2);
+			%      md=extrude(md,15,1.3);
+			%      md=extrude(md,15,1.3,1.2);
 			%      md=extrude(md,[0 0.2 0.5 0.7 0.9 0.95 1]);
 			%
Index: /issm/trunk-jpl/src/m/classes/model.py
===================================================================
--- /issm/trunk-jpl/src/m/classes/model.py	(revision 18215)
+++ /issm/trunk-jpl/src/m/classes/model.py	(revision 18216)
@@ -462,7 +462,7 @@
 
 		   Example:
-		      md=extrude(md,8,3)
-		      md=extrude(md,8,3,2)
-		      md=extrude(md,[0 0.2 0.5 0.7 0.9 0.95 1])
+				md=extrude(md,15,1.3);
+				md=extrude(md,15,1.3,1.2);
+				md=extrude(md,[0 0.2 0.5 0.7 0.9 0.95 1])
 
 		   See also: MODELEXTRACT, COLLAPSE
Index: /issm/trunk-jpl/src/m/extrusion/project2d.m
===================================================================
--- /issm/trunk-jpl/src/m/extrusion/project2d.m	(revision 18215)
+++ /issm/trunk-jpl/src/m/extrusion/project2d.m	(revision 18216)
@@ -2,9 +2,7 @@
 %PROJECT2D - returns the value of a field for a given layer of the mesh
 %
-%   project 'value' vector taken at layer 'layer' from extruded 2d-3d mesh onto 2d mesh 
-%   used to do the extrusion. This routine is used to compare values between a 2d-3d mesh
-%   at a certain layer, and the equivalent value (if it exists), on the original 2d mesh. 
-%   This routine relies heavily on projections (contained in 3d model md) recored during 
-%   the extrude operation.
+%   returns the value of a vector for a given layer from extruded mesh onto the 2d mesh 
+%   used to do the extrusion. This function is used to compare values between different
+%   layers of a 3d mesh.
 %
 %   Usage:
@@ -12,5 +10,6 @@
 %
 %   Example:
-%      vel2=project2d(md3d,md3d.vel,2);
+%      vel2=project2d(md3d,md3d.initialization.vel,2);
+%      returns the velocity of the second layer (1 is the base)
 
 %some checks on list of arguments
Index: /issm/trunk-jpl/src/m/extrusion/project2d.py
===================================================================
--- /issm/trunk-jpl/src/m/extrusion/project2d.py	(revision 18215)
+++ /issm/trunk-jpl/src/m/extrusion/project2d.py	(revision 18216)
@@ -5,13 +5,8 @@
 	returns the value of a field for a given layer of the mesh
 	
-	project 'value' vector taken at layer 'layer' from extruded 2d-3d
-	mesh onto 2d mesh used to do the extrusion. This routine is used to
-	compare values between a 2d-3d mesh at a certain layer, and the
-	equivalent value (if it exists), on the original 2d mesh.	
 
-	Note: for consistency with usage in ISSM, layers are indexed starting
-	from one.  This routine accounts for the fact that python indexes from
-	zero.  In other words, when using this function consider the bottom
-	layer as layer=1.  
+   returns the value of a vector for a given layer from extruded mesh onto the 2d mesh 
+   used to do the extrusion. This function is used to compare values between different
+   layers of a 3d mesh.
 
    Usage:
@@ -19,5 +14,6 @@
 
    Example:
-      vel2=project2d(md3d,md3d.vel,2)
+      vel2=project2d(md3d,md3d.initialization.vel,2);
+      returns the velocity of the second layer (1 is the base)
 	'''