How do you get hollow new terrain schematics to build in survival?
Hello.
I plan on building new terrain on my survival world by building the terrain in creative then making it into a schematic, but am unsure how to impose the new terrain without it conflicting with the old. I want to build the new terrain over any old terrain while having it hollow in the schem to save resources, as many youtubers do. Yes, I know of the hollow command, but when I use it leaves a flat piece on the bottom, and it has undesirable conflicts with old terrain.
An example of what I would like to do is Jermsyboy's video here: https://www.youtube.com/watch?v=73uYauTPLW4
I'm just curious on how he was able to have his schematic interact so well without interfering with the old terrain. Did he build it in creative from the bottom up, block by block instead of using tools like sphere? I'd like to do something like this after building the terrain up with spheres and then shaping it afterward. But when I do it this way, the bad interactions with the old terrain I mentioned earlier occur. Please let me know if my question is confusing, thanks.