This workflow shows how you can measure an object's length in y-dimension f(x) for each x-value it spans. This can, of course, be generalized for measuring in any dimension. The workflow also calculates the change of length as a backward difference f(x) - f(x-1).
This is a companion discussion topic for the original entry at https://kni.me/w/_wHN5jOfXtFC7-ig