Complex sentence: Profilometer is a measuring instrument used to measure a surface's profile, in order to quantify its roughness, vertical resolution is usually in the nanometre level, though lateral resolution is usually poorer.
Split into simpler sentences: Profilometer is a measuring instrument used to measure a surface's profile, in order to quantify its roughness. Vertical resolution is usually in the nanometre level, though lateral resolution is usually poorer.