[Kamui]

I am using NX11 to draw my aerodynamic devices. Once I am finished with the project I export it as .stl file. As option I use 0.080 = chordal Tolerance (I want to go at 0.0025) and 18 = angular tolerance (here I want to try 1). At the end I import all my devices in StarCCM.

Where is the problem? I tried to export three types of configuration of the car: simu000 I loaded the car in NX and then exported, simu002 I rotate the car with the 3D mouse and exported, simu001 I closed the NX file and reopened and reloaded the same car (I want to underline that the car is always the same, with the same pieces). I ran all three simulations with exactly the same Macro (I generated three macro: Straight, Heavy braking, yaw, for this experiment I used Straight) and what I got, was a bit strange: with two simulation I had the same results (simu000 and simu001) but with simu002 I received different results. To find the problem I exported from NX the .txt file and I compared all three files. What I discovered is that in some aero devices there are different mesh.

This is an exemple:

simu000 : facet normal ni nj nk simu001: facet

normal ni nj nk

outer loop

outer loop

vertex 0 0 0

vertex 1 2 3

vertex 4 5 6

vertex 9 8 7

vertex 7 8 9

vertex 0 0 9

endloop

endloop

endfacet

endfacet

The triangles have a different normal and different vertex.

What can I do to avoid this problem? The problem is in the meshing of StarCCM or NX?

In StarCCM I make a surface wrapper -> surface remesher -> trimmer -> prism layer.

I really appreciate your effort to help me.

Thank you;

[me3840]

If NX is for some reason not outputting consistent STL files, why not just export it in a CAD format instead.

[Kamui]

Originally Posted by me3840

If NX is for some reason not outputting consistent STL files, why not just export it in a CAD format instead.

ok now I try to export .prt file