I know the v-blocks or actually degreeing it is the best way, but for a quick ball park, I've been able to come close with calipers...
I was trying to offer a quick easy check for the layman, not everyone has v-blocks or is willing to degree their cam to find out what it is...
The lift at the lobe is the difference between the base circle and the lift at the nose. Since the camshaft spins at half the speed of the crank, the duration of the lobe is never over 360 crank degrees, which can means that the base circle should be able to be measured perpendicular to the peak of the nose of the lobe since the lift should be done in less than 180° of camshaft rotation. I have a few stock 360 cams that I've been able to measure this way and come within less than .005" of what the advertised spec for lift is.