Hi marzRX, yes if you form your object as a closed solid then it will automatically orient the normals towards the outside of the solid.

Usually it is easiest to cut a solid using boolean difference with another solid as the cutting object instead of Trim. Trim is more of a low level operation, booleans are kind of like a batch mode where they combine trimming and automatically discards pieces based on what volume they are contained inside of and then automatically joined as well.

- Michael