3d structured mesh
 

Hi friends
I post a thread about my problem in meshing with Gambit.
my model is a furnace with 72 eliptic holes around it.I want to remove some holes from the section of furnace which was shown in attached photos. I do not know how to mesh my volumes to have a structured map mesh.
I used to create surface and then substract it frome the surface of volume to call them inlet in my model but some one told me to create them as volumes. I want to have a map mesh or cooper but I do not know how to create it. :(
please help me if it is possible for you

thanks

http://i41.tinypic.com/33cx8ut.png

http://i41.tinypic.com/5bz2th.png

http://i42.tinypic.com/autgs1.png

if your elliptic surfaces are the inlet, then I would do a split in the z direction (negative): Use the lower circle adjacent to all your elliptic surfaces and sweep it in negative-z-direction.
Split your volume(s) with the generated surfaces.
Doing that you will isolate all your surface inlet on a volume, which will be meshable with cooper.
BUT for sur you will have a problem (skewness) because of tangential circles (upper and lower) --> possibilities are "merging" or adjusting both upper and lower circle radius for being able to insert one cell between circle and inlet surface