Custom map piece grid dimensions

[Verdite]

Hi old pals

I need to know the grid dimension (grid squares) to use in metasequioa for a basic custom floor piece (flat.)

I found out how to transfer customs... Ive made some nice parts already (somewhat exhaustive) i also
need the obj data for the "tower" piece, because ive got a few round shaped map pieces that require
collision data! ‎ 

Thanks!