[Gmsh] Variable 3D mesh computation time

[Josh Millar]

Hello, 

I’ve noticed recently that the 3D structured meshing computation time (using transfinite line/extrude on a 3-4mil cell geometry) is highly variable. I have not been able to recreate the issue, but have noticed sometimes the meshing will be almost instantaneous (10s), and other times will have to search for each point, and will take upwards of an hour. I am likely missing something fairly obvious. 

Josh