For a dune development project I'm working on I need to make a pre-habitat card with vegetation / habitat types on it. I want to draw some habitat types on a height map of the area, that way combining the habitats seen in the field with the height (for instance a dune valley needs a low height). If I make habitat X with the sketch tool, and then make habitat Y with the sketch tool, I sometimes want to use the lines of habitat X for habitat Y. Not parallel to it, but use the exact same lines coz sometimes they share some lines of course. How do I do that? Anybody I asked seemed not to know it, some said something about Snapping but when they tried it they failed. I hope you all can help me out. Thanks a lot in advance!