edit: Fran, you particularly mention 'thin walled' parts. If you're referring to sheet metal parts i understand
it is normal to extract 'mid planes' and use a surface mesh without 'volume'. I can't say exactly what Aurora can do in this situation, you have to see the theory manual -sorry. However, follow what is said below for better meshing.
Well, you're not the first to scratch their head with the meshes provided using Auroras Tetgen meshing.
Aurora needs a 'good quality' .stl or .stp. and in the manual there are hints as to CAD output parameters to assist.
My software didn't have the output flexibility so i experimented with changing the facet accuracy up / down
globally and changed facets on individual faces etc. all with some limited success. Generally, i got better ( but not ideal) results by viewing the CAD part in 'wires' and changing the facet accuracy on a face by face process and saving/inputting a .stp file into Aurora.
ALL THIS CHANGED when user 'selopez' came up with a procedure that is extremely reliable for a good Aurora input .stl and it also assures a fast FEA mesh using Tetgen of very complex geometries.
Please goto ''forum/V2 freeware/'How to' and choose THE NETGEN/TETGEN CONNECTION by selopez (at page bottom).
open up document ' Glrt19...etc - message will say it cannot be found here ,then asks 'open in new window?'
accept this. ( you may need a google account for this to work - i did!)
Then the document of selopezs' opens up. He has made a tremendous effort to understand what are the
problems with poor quality .stl's / .stp's and why they sometimes crash or freeze Aurora.
It is a long document and i do not understand it all. HOWEVER, there is a procedure at p11 chapter 2. Optimization of T16 meshes from .stl models (POM).
This outlines free software called NETGEN ( inc. link) that allows you to import .stl / .stp / .igs and visually ( and automatically) analyse them for errors, autocorrect errors and many options for refining meshes globally or individual faces to say improve a facetting on a round / sphere / fillet etc. It can then output an assured high quality .stl which when loaded in Aurora, be converted into 3D Tetgen mesh VERY easily and FAST too.
Following 'Selopezs' guidelines, what you see in Netgen as an external / surface mesh, can be almost exactly
what Aurora's Tetgen 3D volumetric meshing will follow providing you choose a similar maximum edge length
as Selopezs' recommendations.
I see that version 5.0.0 of NETGEN has been published. It has parallel processing support. However, it is not an 'easy windows install' procedure but take a look if you're confident. I use version 4.9.13 - i managed to load it ok so it isn't difficult.
It's fast , reliable, mesh flexable / adaptable. The only down side is there's no usual 'help'
If you use 'selopezs' guidelines it will work well. It does for me very nicely.
hope the helps..
ps. something random here. Use version V2a - big benefits. And, if your models are small / medium sized,( see the theory manual for definition of size), i have discovered that the Pardiso runs at x10 ~x14 faster than SICCG / SORCG processes but large amounts of RAM memory is required or it will crash!