importing a meshed model

[ahilbert3PCG3]

I have a very large model that I can break up into 3 smaller assemblies.  When I attempt to mesh the entire model parts do not mesh.  I open the smaller subassembly and can mesh the modeled parts.  I am trying to do a modal analysis of the entire model.  Is there a way to import the smaller meshed subassemblies into the larger assembly?  Any suggestions would be appreciated.  I am unable to share the model due to the sensitivity of the project.

[John_Holtz · Accepted solution]

Hi @ahilbert3PCG3 

Are you using Inventor? What version of Nastran?

The answer to your question is no: Inventor cannot import a mesh from another file. Nastran works off of the CAD model.

I suggest that you hide all the parts, or hide the parts except for the one that is not meshing. Can Nastran mesh the model now?

John

[ahilbert3PCG3]

I am using Inventor 2024 and NASTRAN 2024.  I can mesh a subassembly outside of the main assembly without errors or I can create a mesh control to fix any mesh failures.  However, when I go back into the main assembly the same part does not mesh.  I wanted to know if there is a way to take the good mesh and import into the main assembly.  The main assembly is very large with hundreds of parts.  This may be beyond what NASTRAN can handle at least for now it seems that way.  I have saved parts to step and then reinserted them into the subassembly and then back into the main assembly without success.  I am now trying to do everything within the main assembly.  Trying to fix issues at the lowest level.  I have excluded everything except the parts I am trying to mesh.  So far, not getting anywhere.  Will keep trying.

[ahilbert3PCG3]

In addition, I have found that in some cases I have two identical parts used in two identical assemblies, mounted on one panel and one of the parts will mesh but the other does not.  Not sure how or why that happens.

[John_Holtz]

No. You cannot create a mesh in one model and use it in another model.

• Inventor only works with CAD data, not analysis data.
• Inventor Nastran only works off the current CAD model, not the model or setup in another file.

This is the article I had in mind that suggests hiding parts to get them to mesh. Mesh fails with no message on some parts in Inventor Nastran (autodesk.com). The behavior was the same as your description: a part would not mesh in an assembly, but would mesh by itself. I suspect the problem is related to tolerances. Essentially, the "envelope" of the assembly is different than the "envelope" of the part alone, and therefore tolerances that determine what faces are stitched to what faces changes.

John