Gambit bug on very simple 2d Faces?!
 

I need to make a 2d domain with holes/voids. Lets say we draw an annular square. Begin with 100 by 100 meters and subtract a centred square of 30 by 30 meters. We get an "Annular square" that shoud be submappable....or not?

Gambit do submap it (with 1 m grid size) but with distortion (of one meter) and I do not understand why. I tried to change the vertex types but no chance. By default, it uses the four exterior vertexes as "End Vertexes" and the 4 inside vertexes as "corner vertexes". I can do the right grid but decomposing the above domain to half of it (creating to equal "U" linked domains.

Is there any solution to grid the complete domain directly?

Thanks,

Xie