FDTD vs. FIT for simulating human body with the highest possible number of voxels

Hello!

I′ve to decide between FDTD (in my case SEMCAD) and FIT (CST MWS). I want to simulate a human body with highest possible resolution (number of voxels).

I tested both and MWS seemed to be the better program at the most things, but when I tried to increase the number of voxels over 4.000.000 MWS had too less memory. SEMCAD was able to calculate abaout 15.000.000 (both trials with 2 GB RAM).

Did I do anything wrong with CST MWS or does FIT need so much more memory than FDTD?

Thanks for all comments

mika

FDTD and FIT are very similar so I dont think there should be so much difference in the memory requirement...check out the size of the calculation "box".....maybe you can make it smaller and still fit you model..........

Could you upload your human body model for CST.......or the voxel data??

If I understand correctly, your "highest possible resolution" means smallest possible cell size. Using the same cell size in MWS and Semcad doesn't necessarily mean the same accuracy in the final answer (field values or SAR). With the same cell size, you should expect the FIT to give higher accuracy in modeling the irregular shape (of human body). With the same resolution (the same number of cells), you should expect the FIT to consume more memory, since at least some extra memory is required to record the information related to the irregular shape.

Actually, voxel seems to be a geometrical entity not a simulation grid. Complicated objects like human bodies are approximated by a collection of simpler objects.
Thus the difference between the two programs it is probably given by the actual meshing.
I think MWS, or at least the particular settings you are using, give you a denser mesh.

Thanks for your comments!

Yesyes, I know, the highest possible resolution depends on which model I use and so on, but when I try to simulate the same geometry in SEMCAD and CST, there was this difference in possible number of voxels.
And so I would be intrested to know, if this was maybe a mistake from me, when I used CST MWS (I tested CST only for two weeks and I simulate with SEMCAD for some years) or this difference in number of voxels is founded in the difference of FDTD and FIT.
Or could there be any other reason

mika

P.S sorry aaron, my license for CST has expired ...

What I was thinking is to compare (visually) the two meshes for the biggest MWS case - 4.000.000 voxels, and see if MWS mesh is denser, or maybe SEMCAD?s grid neglects more detail. But if your license expired ?