Learning Forum

[Bharath JS]

Hello all,

While importing a Lattice step file, there seems to be an error (Invalid face geometry was encountered that could not be successfully translated) that pops up as shown below.

Meshing is not possible due to this error.

I have checked the geometry in spaceclaim and there is no error in the geometry that spaceclaim encounters as shown:

 

Kindly help with the issue on how to solve it and how to proceed. I need this for my compression analysis of the lattice structure.

 

 

Thanks in advance!

[Sampat Kumar]

Hi Bharath,
It’s warning message. However, I hope you have tried to convert the facetes body into solid body in the SC before importing into the mechanical. 
What kind of error message you received in the meshing?  What type of mesh control you used to generate the mesh. 

Best Regards,
Sampat

 

[mjmiddle]

Try right clicking on the error. If there is an option to "Show Problematic Geometry" see what that shows. Mechanical can work with facets directly, but try converting to solid in SpaceClaim as Sampat suggested:

For facetted geometry, you get many triangles representing the surfaces in Mechanical, which is cumbersome on the GUI (slow to rotate, pan, zoom). In my experience converting to solid usually makes it worse unless you have a large amount of flat faces to merge triangles. For curvy geometry, you just get a lot of CAD surfaces, one for each triangle, which is worse than just having all the facets.

The original intent for the lattice feature in SpaceClaim is for 3D printing. The process of taking to Mechanial and meshing and setting up for analysis has not been streamlined. You may be able to work with it, but it will be difficult. Since the facetted geometry imports as all one body and one face, you can't use a patch conforming method to mesh. You can only mesh with the patch independent tetrahedral mesher. Also, since it is all one face you can't select sections for loads and supports. In SpaceClaim, create named selections by selecting triangles (box, polygon, lasso selection). Then in Mechanical you will have separate patches you can select for loads and supports.

[Bharath JS]

Hello Sampat,

Thankyou for your response. 

Yes, I have converted the faceted body into solid body in SC before importing into the mechanical. I have used 'Convert to solid > Do not merge faces' option.

I did not encounter any problems in SC but after importing into Mechanical the problem arises.

 

Meshing was not able to proceed due to this issue.

[Bharath JS]

Hello mjmiddle,

Thankyou for your response. 

Yes, I have converted it into solid in SC and then used that in mechanical. But still the issue persists.

Thankyou for the info on the meshing strategy, I will try and let you know. I am planning to make top and bottom plates to act as compression plates. I have heard that this works better than named selections. Nevertheless, I will try this method as well.

Is there any other way to import a lattice .stl file for compression analysis?

[mjmiddle]

Importing an STL should not be the problem. Meshing and setting up analysis would be the big problem. When did the face error occur? Did it occur when transferring from SpaceClaim to Mechanical? I suspect it occured when trying to mesh with the default patch conforming mesher. Setting up named selections is only to allow you to select those top and bottom faces for bounary conditions.

[Bharath JS]

Hello mjmiddle,

Thankyou for your response. 

The error was encountered when importing a step file into mechanical. This warning was seen before meshing itself.

[mjmiddle]

Why did you convert to step? You probably have 100,000s or millions of small triangle surfaces. Try using the lattice in SpaceClaim and go straight to Mechanical. Do not try to convert to solid and do no try to export as a 3rd party. Just set up named selections for BC selection by selecting groups of facets.

[Bharath JS]

Hello mjmiddle,
Thankyou for your response. 

Will try the method you have suggested. 

[Bharath JS]

Hello mjmiddle,
Thankyou for your response. 

Will try the method you have suggested.