Single peak-to-valley height Rzi is the sum of the height of the largest peak height and the largest pit depth of the roughness profile within a profile section lsc.
Roughness depth Rz is the arithmetical average of the single peak-to-valley heights Rzi for consecutive profile sections:
Maximum roughness depth Rmax is only still defined in VDA 2006 and ASME B46.1 as the largest single peak-to-valley height within the evaluation length le.
In DIN EN ISO 21920 the new parameter Rzx is introduced instead of Rmax.