A workpiece is measured by a contact detector. The contact detector is moved relatively towards a workpiece. A characteristic of the contact detector that changes as the contact detector contacts the workpiece is measured at a plurality of times. A projected time when the characteristic of the contact detector will meet a predetermined threshold is extrapolated from the characteristic measured the plurality of times and using a processor of a computer. A trigger is set to measure coordinates of the workpiece at the projected time. Coordinates of the workpiece are measured at the projected time based on the set trigger.