How to use dynamic topology for terrain modeling I tried to get some hills and valley on a 2x2 Km plane with dynatopo, but it is invisible as it seems to be limited in the height it can produce. How can i get it to make bumps that are realistic for that use (100m big or even more) ? 

Notes: I know the solution using subdivided planes and proportional editing but it is not as powerful and flexible.
As it as to fit the rest of the scene, I can't realistically work on a 2m plane and then scale to 2Km every time to check if it's ok and then back to 2m to polish, that back and forth is way to time consuming.
Try applying scale to the object, with CtrlA > Scale.

There shouldn't be any limit to the height you can sculpt, but object scaling might make the sculpting influence too small. Also this is probably a general sculpt mode problem not specific to dynamic topology.