This describes the steps I used: 1) once median curve is established, put a datum point on it.  The location of this point can be specified in 2 ways: as a ratio, or as a along-the curve distance from an end of the curve (I chose the ratio scheme).  Let's refer to this point as P1.   2) create a datum plane that goes through the point P1 and which is parallel to the default yz plane.  Let's call that plane D1   3) Create a sketch on D1 and as a reference, choose the point P1.  In my example, the sketch is just a vertical line and a constraint is added that makes the reference point P1 be the midpoint of this line.   4) Once sketch is accepted, I "absorb" the datum features P1 and D1 into it.  You do this by dragging them onto the sketch in the model tree.  This way you get a single "superfeature" which is controlled by 2 dimensions - the distance along the curve, and the length of the sketched line.   5) I then generate a table pattern of this superfeature and use its 2 dimensions as the variables in pattern instances.   6) Then the inside / outside curves are constructed by manually collecting the points generated by the pattern.   --- I assume your "another question" pertains to building the cross-section for a revolve feature? So yes, you can trace the curves generated in step 6 above using the "project" tool you describe.  This is the standard method.  Another method would be to skip generating the curves in step 6, and then build your sketch directly using the points generated in step 5 above (essentially, you'll specify a 50 point spline in the sketch itself).   In either case, you have to go through the pain of selecting 50 datum points.  This is one of the reasons (and it's a big one) that I think the method of importing / updating externally generated  .pts data is superior.  That and the fact that the table-editing tools available inside of Creo are pretty poor (compared to MS-Excel, for example).   Final note: if you do choose to use this techinque, you will have to make some changes to the procedure - because if I recall correctly, your thickness calculations are based on the distance along the axial direction of the diffuser (and not the distance along the median line).     ... View more

Ok, I couldn't resist taking another look and came up with this method that you might find useful:   Edit the pattern table to tweak the thickness values.     ... View more

I think that you should re-consider your approach, because you seem to be under the impression that you will have to re-build the guide vanes and struts and the rest of your model if you ever go through the "update values" process (illustrated in an earlier post of this thread).   Anyway, it does feel like we are talking past one another, so I will just say "Good luck!" ... View more

I have to tap out of this one as I can't open your files (you are using Creo 4.0?)   Anyway, I'm baffled as to why you are bringing in the meanline .pts data (calculated outside) and then trying to parametrically generate the inside/outside diffuser sections using creo.  How will you be tweaking these 50 thickness values?  - by typing in individual values, regenerating, and trying to visually obtain smooth surfaces?   Have you considered doing all your calculations outside, bringing in just the inside / outside curves and then building the rest of your model??? ... View more

Ok, so where is the difficulty?  Defining relations is a core functionality of Creo... ... View more

Sounds like you could be using a variable section sweep driven by a graph.  The graph would allow you to define the thickness of the diffuser section along the trajectory.  Here's an example: Creo 3.0 files attached for examination of the modeling technique.     ... View more

Curious; how did you determine what these 50 constants are?   I don't know the problem you are trying to solve, but here are some thougths: 1)  you seem to have been trying to edit the points by modifying the values in the .pts file used to create them.  As you discovered, that does not work because there is nothing linking the .pts file to the model.  However, it still might be easier to edit the .pts file externally (e.g. using notepad++ or excel), save it, then edit the definition of the point feature, delete the previously imported points from the table and then "import" the updated .pts data.   2) To generate the 2nd curve, ge nerate a copy of the imported points to produce an identical set of points as in step 1.  Then edit the relations of this 2nd point feature - and here you have to do the  grunt work of writing a relation that describes the x,y,z coordinates of each point in terms of the the x,y,z coordinates of the corresponding point in the 1st point feature.  To assist in this, I suggest you right-click on the points features and use the information->feature information tool and look at the last table in the information page - it will show you what dxxx symbols the system assigned to the coordinates.  Also, I think you will have to use the $ in your relations (i.e, they wll be of the form $d0 = $d150 + const/2) so as to keep track of the sign.   3) to generate the 3rd curve, copy + paste the points+curve from the 2nd step and edit its relations.   Yes, in total you'll end up with 300 lines of relations, but with copy and paste it shouldn't be that tedious... ... View more

It seems that you are simply shifting the copies - in your equations, the shift is in the y direction according to some constant value.   So maybe you could just select the points feature (I assume you used the feature point -> from offset coordinate system) and do a copy (CTRL+C) then paste special -> Check Apply move/rotate transformations to copies and then specify the y axis of the coordiate system as the translation direction...  After the feature is built, you could add the relation to it... ... View more

You maybe could also look into this threads: Create DXF   also: how to export each sheet as separate dxf from drawing file   ... View more