Can I create slabs, stairs...
You can't create solid custom slabs, stairs and solid placeable items other than blocks. Problem is that Minecraft would show them as transparent blocks because of this bug: https://bugs.mojang.com/browse/MC-54254 You'll be able to create custom shaped blocks when Mojang will fix this bug (adding a special tag that can be turned on or off, now it's always on. "Opaque").
Example that shows this Minecraft bug (2014 screenshot, I hope they'll fix...)
Copy link