In any alignment situation, one of the most basic principles is rise over run. Think of it as a change in offset over a distance. It is also a way to quantify angles without using degrees. When the laser system measures “angularity”, it expresses it as rise over run, or a change in offset over a distance. This information, along with the dimensions that the user enters are what the system uses to calculate corrections at the feet. That is why it is very important that laser measurements are repeatable and that all dimensions should be accurate to within 1/8 inch. The sensor to coupling dimension is the most critical of these. If the laser measurements are good but the dimensions for the feet are not, any corrections the computer calculates will not work due to the fact that they are “applied” to a different location, not at the actual foot location. If you are making the corrections that the computer says to and your alignment is still off, double check your dimensions.