3D laser markers attribute 3D surface engraving capabilities, permitting for precise, uniform marking within a tolerance height range of 0-60mm with out requiring refocusing. ? v ? ? t + ( v ? ? ? ) v ? = ? one ? ? P + v ? v ? + ? g ? ? T \displaystyle \partial \overrightarrow v \around \partial t +( \overrightarrow v *\bigtriangledown ) \overrigh