typically, construction of a Torii (hey! it has a name!) consists of two posts (ascention), a lintel with the curved kasagi (top part representing the spiritual world), and tie beam (the natural world).
As a note, it's perfectly fine to have the characters walk past this gate, but to have characters going through or - jesus -
jumping on top of religious structures is not the most respectful thing to do
. They represent a transition (artistically, physically, and philosphically) into holy or otherwise peaceful ground, so try to be careful as to where you position them.