Meshing in ICEM using Octree mesh algorithm
 

Hi,
I need the help of all the ICEM experts. I am trying to mesh a place with plenty of buildings, of which some of them are complex. This has to be done in 3D. I have been trying for almost 3 weeks now but I'm still getting errors in computing the mesh with tetrahedrals. I tried to mesh one building and brought it into fluent but I can't even get that right because it gives me negative volume when i imported it in. And sometimes I have a hole in my mesh( which i do not know how to fix).
I have always been a fan of blocking and that is pretty much how I create all of my previous mesh. But this is a case where blocking is simply impossible. Can you offer me some tips?

I have attached my nightmare geometry to this post. Many thanks in advance.

run a geometry repair, it will look for the holes you have and close it... tell us how it goes...

will do, Ali. But I am now thinking if it is possible to break this cfd simulation into parts. I could simulate, say for an example, 1/4 of the geometry and then use the results from that simulation as an inlet condition for the other parts. Is this ridiculous?

Ok.. as promised, the mesh is attached. I did a geometry repair. For the benefit of those who do not know what i meant by that, it is a procedure in ICEM to make sure there are no leakages. and what i mean by leakages is holes in the geometry that will affect your mesh when using the octree algorithm.
So what i did was set the tolerance really low. Once i did that, i put in a script to determine the maximum size on each edge. I initially tried putting number of nodes on each curve but this did not work out too well. Thanks for all the help, Ali, Stu, Far and all.