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NURBS surfaces on a wing

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Old   January 25, 2017, 00:27
Default NURBS surfaces on a wing
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Ferruccio Rossi
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Hi all,

I am meshing an airplane wing inside an enclosure. Both pictures show only the wing surfaces inside the enclosure (the enclosure faces have been hidden). I am using two different modeling methods:

METHOD 1: import 3D curves of the airfoils and obtain the wing with few surfaces (pic 1)

METHOD 2: import coordinate points and obtain the wing out of many surfaces (pic 2)

As you can see from the pictures, METHOD 1 is clearly preferable to work with, but when I open the mesher it says "The following faces have high order NURBS surfaces. These may take longer to mesh"
And the mesh takes forever!
On the other hand, if I use method 2 the mesh takes a normal amount of time.

Any idea on how to solve the problem? I would prefer to work with METHOD 1 since there are only a few surfaces on the wing compared to the hundreds of surfaces of METHOD 2.

Thank you for your help.
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Old   January 25, 2017, 07:22
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Glenn Horrocks
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Try importing the solid geometry with a different solid model format. Parasolid is often the best one, but if that does not work try STEP, ACIS or IGES.
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Old   January 25, 2017, 18:09
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Ghorrocks,

Thank you for you answer. But I modeled the wing into Design Modeler. As you can see from the picture, the wing is inside a fluid domain but it has been removed using a Boolean operation. So what is left is just the hole left by the wing inside the fluid.

Following your suggestion, I exported my wing as a Parasolid file and then I imported it again as a Parasolid file and remade the enclosure around it, but it still generates NURBS when I open the mesher.
Any ideas? I am stuck since it takes forever even to generate the simplest mesh without any modification.


And which format is better between Parasolid text and Parasolid binary?




Best regards.
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Last edited by frossi; January 25, 2017 at 20:22.
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Old   January 26, 2017, 01:31
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There is no difference between parasols text and binary files, other than the obvious. The solid model data is the same.

If you are getting these problems with a design modern geometry than no import/export is required. It shows something is likely to be wacky in the way you drew the geometry.
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Old   January 26, 2017, 02:36
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What about geometry simplification...

https://www.sharcnet.ca/Software/Ans...BodyOpSimplify

I had same problems and it worked, just make sure it doesent change the geometry too much, it usualy doesent.
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Old   February 5, 2017, 16:27
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thank you for the hint urosgrivc, but is still doesn't work
Although I selected Simplify, the geometry still generated NURBS when I imported it into the mesher.
So I had to use my METHOD 2 (wing with many surfaces) and there were no more NURBS.

Still, thank you for the suggestion, I learned something new
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