[Gmsh] import + meshing of step file

[Geordie McBain]

2010/10/15 jb.leydet <jb.leydet at laposte.net>:
> Hello,
>
> I'm facing a problem with gmsh:
>
> I'm trying to import and mesh a step file. All surfaces seem to have meshed properly, but then I get an error while trying to mesh the volume.
>
> I attach the error text (featuring some weird "Info : Starting subloop 4 in Line Loop 4 (are you sure about this?)" messages... maybe that could be the source of the pb?).
>
> I also attach the original step file and the final geo file.

I found that I could mesh this coarsely.  I created a file
air-channel.geo containing just the line

    Merge "air-channel.stp";

then meshed it on the command line with

    $ gmsh -3 -clscale 0.2 air-channel.stp

(equivalent operations are available in the GUI too).  This worked
O.K. with different values of clscale, like 0.5 and 1.0 (quite coarse)
but did fail for 0.1; the error was different from yours though (which
might indicate some progress?):

Error:  Invalid PLC.
  Two subfaces (733, 7035, 7415) and (759, 7273, 7016)
  are found intersecting each other.
  Hint:  Use -d switch to find all intersecting facets.

I didn't follow up the hint, as "-d" isn't a known option for my Gmsh
(2.5.0, compiled from SVN a couple of weeks ago, on 64-bit Linux Mint
8).