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Need help with Geometry cleaning techniques

Experimenter
Experimenter

Hello, 

I am trying to clean this .Stp file with geometry cleanup and mesh generation tools. It is not working . 

Can any expert take a look at the model and help with it a clean models please. 

Its urgent for my thesis. 

 

Regards, 

Srikanth N 

3 REPLIES 3

Re: Need help with Geometry cleaning techniques

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Hello!,

This is typical when importing STEP files specially from CATIA V5, terrible patched, not problem, if I run GEOMETRY > SOLID > CLEANUP command I get the following:

Solid Cleanup
1 Solid(s) Selected...
Beginning Cleanup of Solid 1...
  Removing Redundant Geometry...
    Found 87 Redundant Point(s).
    Found 71 Redundant Curve(s).
  Cleaning Geometry...
    No Cleaning Performed on Geometry.
  Removing Small Features...
    14 Small Edge Chain(s) Found.
    Small Feature Removal Complete.
  Optimizing Geometry...
    Geometry Optimization Complete.
  Saving Updated Geometry...
  Checking Geometry...
Self-intersection near (-53.07134, -0.5, -41.71004).
Self-intersection near (-52.69658, -0.5, -41.5631).
Curve 2921 is invalid or corrupt.
    Failed Geometry Checking.
Cleanup of Solid 1 is Complete.

The workflow always is the following:

  • Search for short edges: make sure to import your geometry in millimeters (set SOLID geometry scale factor = 1000 under FILE > PREFERENCES > GEOMETRY) and go to the MESHING TOOLBOX and search for short edges, this will give you and idea of how small your short edges are in your FEMAP model: if 0.00057 or 10.05, etc..

short-edges.png

  • Most of the short edges can be removed using FEATURE REMOVAL > POINT, use it , is really powerful.
  • Other not, because the point belongs to more than one curve, then you will have to use COMBINED > BOUNDARY SURFACES > ADDD BY CURVE, this is your main resource, use it.
  • At the end when the geometry base is OK then perform a 2-D mesh of all solid surfaces using 2-D triangular elements,previously to any 3-D solid tetrahedral mesh: if you arrive to a valid 2-D mesh (check element quality using TOOLS > CHECK > ELEMENT QUALITY command repeatedly), this is the best warranty that your 3-D solid mesh will be OK.
  • Your can split the 3-D solid surfaces to create regular well shaped 4-curves-only surfaces when available, this way the resulting mesh will be more structured & mapped mesh, especially in regions where high stress gradients are present. You have plenty of tools here under GEOMETRY EDITING like POINT-TO-POINT, POINT-TO-EDGE, etc..
  • And finally mesh your geometry with 3-D solid TETRAHEDRAL elements, use defaults options.

 

To learn more take a look to the following videos:

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Need help with Geometry cleaning techniques

Experimenter
Experimenter

Firstly very much thank you for quick reply. 

can you help with doing this , You are an expert and can do it quickly than me. I have to submit my thesis tomorrow and struggling to complete this. 

Please can you clean the cad and send me. 

I will appreciate your help for life time. 

regards, 
Srikanth N 

Re: Need help with Geometry cleaning techniques

Siemens Phenom Siemens Phenom
Siemens Phenom

Depending on what you are looking for and the areas that are "bad", you might simply try running Mesh->Geometry Preparation. It can often allow you to mesh over problem areas and still get a valid tetrahedral mesh.