Complex sentence: The breakwaters were modeled, as it happens in the full size construction or in physical laboratory test, by overlapping three-dimensional elements and the numerical grid was thickened in such a way to have some computational nodes along the flow paths among the breakwater's blocks.
Split into simpler sentences: The breakwaters were modelled, both for the actual size construction and for a physical laboratory test, by overlapping three-dimensional elements. The numerical grid was thickened in such a way to have some computational nodes along the flow paths among the breakwater's blocks.