I'm working with some nice castings I made, and I'm curious to know some of the different techniques that are used to transition between castings. There's always a gap of sorts between each outcropping. How do you fill the bigger gaps so they look natural? I've seen some foliage hide the transitions, but what if you want just rock? I'm reading that chipping the edges with a screwdriver can work, both before and after placement...are there any others?