STL->SolidWorks->IGES->Caedium = Slow

I'm doing analysis of hydrofoils, starting with an .stl, hoping to do RANS CFD analysis.

I can modify stl with SolidWorks to an IGS or STEP file. Importing the .igs with Caedium seems to take forever though. Is this because the program is attempting to volume mesh the igs immediately upon import? Not sure what the quickest method to a usable RANS volume mesh will be; suggestions appreciated.

[Edit: based on an email exchange]

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STL is a lousy format

I'm not aware of any good STL to IGES or STEP converters. I'd guess that SolidWorks is converting each triangle (could be thousands) in the STL file to a planar three-sided geometry face and exporting those. As a test, try re-importing that IGES file back into SolidWorks to see if this is in fact the case.

Caedium does not try to immediately mesh imported geometry. I think the slow down you are seeing is because of the large number of individual geometry faces in your file.

STL is a lousy format which we do not support for volume meshing, as I guess you know already - hence the conversion you tried. For more details try the forum post "simulation flow over sailing yacht appendage"

Where did the STL file originate? If it was from a scan then you are pretty much stuck. However, if it came from a CAD package, maybe you can get hold of the original 'good' geometry.

There are packages, such as 3-Matic from Materialize, that can convert scan data to CAD geometry, but they are not cheap.

If you are looking to simulate a fully immersed hydrofoil then you should be good to go with the RANS Flow capabilities. However, we don't yet have a multi-phase (water + air combined) capability.

Re-import the igs to Solidworks

Unfortunately it is out of a limited package. But Solidworks seems to deal with it as long as the STL resolution is not too high. Of course this makes me worry that the facets will throw the flow analysis off.

I will re-import the igs to Solidworks and see what it looks like. Thanks for your responses.

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