# Extract Surface Data from 3D-Plot

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 December 22, 2016, 08:20 Extract Surface Data from 3D-Plot #1 New Member   Join Date: Dec 2016 Posts: 5 Rep Power: 9 Hey everyone, I am currently trying to extract CFD surface data from the 3D-Model of a blade tip. In other words, I want to extract the coordinates and cell data from one 3D surface area of the blade and then Project those on a 2D-plane. Unfortunately, I could not get on with this point so far. So any Ideas/Suggestions are very appreciated. Thanks!

 December 22, 2016, 15:33 #2 New Member   Germán Salazar Join Date: Apr 2015 Posts: 16 Rep Power: 10 Say, what kind of elements is your 3D model made out of? Also, Are you asking how to do it withing tecplot itself or any other way? Not knowing tecplot well, my two ideas include writing some code to retrieve the information.

 December 23, 2016, 00:57 #3 New Member   Join Date: Dec 2016 Posts: 5 Rep Power: 9 Hi, thanks for your reply. I am interested in any method to extract the data, so it doesn't need to be in tecplot. The 3D Model ist made out of FE triangles.

 December 23, 2016, 07:06 #4 New Member   Germán Salazar Join Date: Apr 2015 Posts: 16 Rep Power: 10 So, if I understand it correctly:you have a 3D surface made out of triangles, you have a model of a blade, and interested in retrieving the blade-tip cells Assuming the radial direction of the blade is in the same direction of the z-axis, how about you simply calculate the normal of each cell and if it is "mostly" in the z-coord, then it is "flat" enough to be declared a tip cell. By "mostly" in the z-coord, you can try different values and see which one works, this is simple; for example, for a given cell, if the z-component of the normal divided by its own length > 0.75, then we have "flat" enough cell to be declared a tip cell. In order to stay away from similarly "flat" cells at the root of the blade, you need to calculate the normal and the flatness test only for cells that are towards the top of the blade, say, above the average z-coord of entire blade; or, if you want, you can hard code some known value but this limits the usage of your script with other blades. Is this clear? does it help?

 December 23, 2016, 09:25 #5 New Member   Join Date: Dec 2016 Posts: 5 Rep Power: 9 Thanks for your help! I'll try it that way.

 Tags cfd, extract, surface, tecplot