i KNOW it must be possible to. . . . . .

[-DeToX-]

No. I mean what I said. Campaign switches BSP's as you progress, then switches maps. BSP switching won't sync up properly.

Which is due entirely to the scripts. Scripts are the only thing that won't sync. The only scripts that will sync are ones that spawn things.

Scripts don't sync at all - rather certain actions, like spawning sync. But bsp switching, print commands, cutscene commands, etc, don't sync.

Campaign mission updates along with other campaign traits I beleive also would not sync.
Also Mainmenu tries to spawn things in MP differently than SP, so it would try to setup a game type, spawn netgame, spawn you through player spawns, and many other things that are wrong I believe. But this was long ago since i checked.

[Agent ME]

look at trigger zones as universal triggers because if player1 steps in the trigger both host and client will know that the person is in it, therefore it will synce over SLC, we tested it but I dont have the vid srry

Scripts don't sync at all online.

The host xbox could be running a script, and the client xbox doesn't keep track of it at all - the host doesn't tell the client about what it's doing.
But the host xbox does tell the client xbox when something like an object spawn happens.

To the client xbox, nothing at all happens when you go into a trigger zone, unless it is death enabled. Just because a script has an action triggered by a trigger zone doesn't make it's next actions any more or less sync-able.

[Thrasher Alpha]

For one BSP switching is not supported (Does not sync) over system-link.

it does for me. i got my almost done bsp mod on system link on xbc and played.

[Fleabag77]

Not BSP Conversions, BSP Switching. Multiple BSPs on one map, and switching between them.