[Virtual1ty]

You're trying to recreate the game "Portal" right? Unfortunately I never played it or heard about it so I dunno what you mean by "changing player facing angle on exit portal" but if those portals are like you "drop from a ceiling onto a platform", then the only way I guess would be getting that platforms landing XYZ and determine the angle difference (actually coordinates to get the angle) from the portals XYZ from where you start to "drop" and the platforms XYZ where you land. I don't believe there's any other way AFAIK.