"""""Not exactly sure what is meant here. """""

It has to do with flow analysing the 2 surface structures... When they are disparate, then the result can be distorted a bit...

SO like is the rectangle edges and size the same as the target edges and size? (for 2d) For the 3d surface, the actual structure of the underlying surface matters too. So the target surface, turn on the points for it, then look at the points for the base surface....

There are some demos on the forum that demonstrate the topic.... I am away in cali so can't really get into it too much...