One of the very first Dynamo blog posts I read demonstrated how to place an adaptive fence component so that it would follow Topo. At the time, I thought it was an interesting concept, but not overly useful since I typically use non-adaptive fence components and fences will frequently step (instead of slope) with grade change.
However, not all fences are stepped, and I recently decided to take a look at trying the same concept on a non-adaptive fence. It is quite a bit more complicated than the adaptive version, but there are several reasons why you might not use an adaptive fence component and the concept can also be used to place a stepped fence.