Importing and meshing aircraft surface mesh
 

Hello,


I'm trying to import and mesh surface data from an .igs file, specifically from the open-source NASA Common Research Model (NCRM), which can be found here (DPW4_wb_no_tail_v03.igs.gz).

The model itself is a fairly simple aircraft, with a hole at the symmetry plane. I fixed this up using the "Fill hole" utility, and then fixed the remaining pierced faces and free edges through the surface repair tool. I then created a sufficiently large rectangular skybox to fit around the airplane. When I subtract the two, however, the program will execute it but already complain that it cannot do a CAD subtraction. The resulting fluid volume then looks like the image in attachment. This causes the automated meshing tool to fail and gives an error that the part is self intersecting.

Any idea on why my subtracted part (fluid volume) looks like this? I suspect that is the root cause of the meshing error.


Thanks in advance,

Jarn

Doing discrete subtractions with surfaces that are nearly coincident is very difficult. It's better just to use surface repair to attach your geometry to a box directly.


I should probably be more specific; the extra face you added to the aircraft on the symmetry plane is the problem, in likelyhood. I imagine your tunnel box has its symmetry plane exactly on this surface, which means your subtract is subject to rounding error and won't be very robust.


In addition to just stitching the aircraft to the box, you could also mirror the aircraft and keep your subtract as is. This would eliminate the coincident faces problem.

So, if I understand you correctly, I should take the airplane and stitch it to the tunnel box? So I import both the tunnel box and the airplane model into surface repair, but don't see how I should stitch them together. Using boolean unite?

Combine the box and your aircraft outside of surface repair, then surface repair the resulting part. You can stitch them together with many different methods, the easiest of which is probably to use the imprint tool on the symmetry faces of your aircraft to stitch to the symmetry plane of the box.