Originally Posted by Belanger
It would be different in that the first slice of the part I measure (the front lip) might have the profile tolerance zone on the high side: 80.2 mm from the floor could be the top of the zone. But at another slice of the part (maybe halfway back, into the depth) the profile tolerance zone could be at the low side of the height: 79.8 being the very bottom of the zone.
So the variation of that top surface in the "z" direction could be bumpy to the tune of 0.4 mm, while in the "x" direction no bumps could exceed 0.07. However, if we change the symbol to profile of a surface, there can be no bumps anywhere that exceed 0.07.