A 2D distance 2 dimensional distance, ignoring the 3rd dimension. If you are in the Z workplane it will only measure the distance relative to the X and Y axis. Any distance in Z will be ignored. If you view it as vision and you are looking at two points staring down the Z axis you can't see any change in height in the Z axis. CMM software is the same it only "sees" 2D distances that aren't in the workplane.
a 3D distance takes all 3 axes into account when measuring distance.
A 2D distance 2 dimensional distance, ignoring the 3rd dimension. If you are in the Z workplane it will only measure the distance relative to the X and Y axis. Any distance in Z will be ignored. If you view it as vision and you are looking at two points staring down the Z axis you can't see any change in height in the Z axis. CMM software is the same it only "sees" 2D distances that aren't in the workplane.
a 3D distance takes all 3 axes into account when measuring distance.