round shapes lost using "Split Face" 1

[david36643]

Hello,

i am doing an FEM investigation and try to mesh a complex geometry with NX. I'm frequently using the function "Split Face" to generate a better mesh. This is working perfectly on plane shapes, but on round edges the geometry gets changed! The generated spline, which divides the faces, is shown with low tesselation.


PROBLEM: The faces shape is not round anymore, but fitted to the low tessellated spline. This shape problem is also carried over to generated meshes on this face.


I am searching for something like how to crank up the tesselation from the mentioned spline. I dont want to change the faces from the polynominal structure and try to solve the problem with the "split face" command inside the simulation application.
Someone is able to help?


Regards

David


Vers: Siemens NX 8.0

 

[Toost]

you know that you can pick individual edges and assign a "mesh density " there directly ?

Can you show an example image of what / how it is you do with this split face ?

Regards,
Tomas

 

[petulf]

Have you turned on high resolution polygon models in advanced simulation?

 

[david36643]

Thanks for your replies!

Increasing the mesh density doesnt fix the problem, Thomas. The bad shape is just meshed with a finer mesh. I'm very sorry i can't upload an example showing the problem due high restrictions concerning the geometries.


petulf, please give me a hint where i can find this option.

Regards

 

[cowski]

Are you dividing the face in the original model or in the FEM file (on the polygon body)?

www.nxjournaling.com

 

[david36643]

In the FEM File.


Regards

 

[cowski]

I've had pretty good luck dividing the faces in the original model (or idealized model) file and updating the FEM polygon bodies to match.

www.nxjournaling.com

 

[Toost]

can you create a separate NX file to show how/ what you subdivide , not related to your actual model, and then do a screen capture. and show the image here.?

Regards,
Tomas

 

[david36643]

I have found this workaround also today, but only the "Subdivide Face" command on the idealized part worked well.
But its problematic to correct a face with this method after meshing. A properly working "Split Face" command in the FEM file is still my aim.



I even have no internet connection at the CAE-Workstation. I cant show an visualization from my problem, sorry.

 

[cowski]

When you subdivide the face in the idealized model, you will need to update the polygon body and the mesh. The mesher uses the body faces to help determine where the nodes/elements go. If you subdivide the face after meshing it will subdivide along edges of the existing nodes, resulting in your "spline with low tessellation".

www.nxjournaling.com

 

[david36643]

I can not share that. The subdivide face command always generates a well shaped spline and the updated mesh fits to it. With problematic i have ment, that all faces i have merged in the FEM file with "Merge Face" appear again, because the FEM file gets updated with new polynominal structure. This just makes sense, but as i wrote this workaround is not what i am looking for.


petulfs hint (2nd post) sounds great, but i dont know where to "turn on high resolution polygen models".


Regards

David

 

[petulf]

David: The setting is available through Preferences->Meshing...-> High Resolution Polygon Bodies For more information check out NX help -> Home -> CAE -> Advanced Simulation -> Command reference -> Meshing Preferences dialog box.

 

[david36643]

Thank. you. so. much.

I have to say this does not fix the lines, which are created with the split face command in the fem model. maybe a bug?
Im doing face splitting in the idealized model with subdivide face command now, which works pretty well, but not perfect at all. Till now. The high resolution polygen model option merged this and furthermore all random appearing problems with elements not following the bodys shape (spikes appeared at plane surfaces, edges were meshed with bad shaped meshes). Im happy my models have finally the quality, which i request.