Oneway turnstiles work too. HL2 uses this at the very beginning level in the trainstation. 

add a player counter trigger that activates only once it has been touched by every player. would need new qc though.

possibly fake it with some elaborate counter with timeout, and not enough players are standing on (separate) buttons then it doesn't continue.
sucks if there's only one player though.

one other alternative would be to flood the earlier parts of the map with lava or something. you'd need some teleporter with careful killtarget use to prevent respawning players from dying instantly though.

alternatively place a massive triggered teleporter over the earlier parts of the map and trigger it to instantly teleport lingering players into the arena. would need a teleporter at the start...

or just use one way teleporters so that you can always get in. You could put them behind a door that is toggled when the area starts, and again when it is ended (if desired). 

add a player counter trigger that activates only once it has been touched by every player. would need new qc though.

Easier one would be to put the trigger that targets the counter on a drop down or on a wind tunnel. Would need for the area to be wide enough so only one player passes at the same time and fiddle with the wait key till even if the two players go one right after the other it will trigger for both. 

https://twitter.com/ioquake3/status/952351931535519745 

How very interesting, I'm sure you could talk for hours about GPL given the go. 

I'm gonna share a simple trigger setup you can use to only trigger something once all the players have progressed beyond a "gate" (and then ruin it a bit at the end). We need to build something I call the "dead man's switch".

The idea of "dead man's switch" is that we build a system of entities with an input and an output, where the output fires if we haven't had an input in the past 0.5 seconds. I'm gonna prove it's theoretically possible using spike-shooters and doors - if I put more effort in I expect there's a cleaner way to build it, but that will have to wait until the blog post in a few years time.

Build a spikeshooter, firing continuously at the output trigger: a shootable trigger_once. Now position a door such that the door blocks the spikes when open, but allows them to pass when the door is closed. Make this door return rapidly to closed after fully opening.

Now add the input: a rapid firing trigger_multiple in the actual level which targets the door. So long as at least one player stands in this trigger, the door is retriggered repeatedly and kept in the open position. As soon as this stops happening, the door closes, a spike passes through, and the output trigger fires. The dead man's switch is complete!

How do we use the dead man's switch to create a gate that all the players must pass beyond before the level progresses? By defining the gate in negative terms. We cover all the portions of the level before the gate with trigger_multiple inputs to the dead man's switch. As long as at least one player remains in the pre-gate parts of the level, the switch cannot trigger. As soon as the last player leaves the triggers, the dead man's switch activates.

Now I've shared how to pull the basic version off, here's the first problem: the dead man's switch will trigger if there are no players in the pre-gate region, and one way to achieve that is to have zero living players anywhere in the server! This could happen if all the players die at once (especially easy if there's only one in the server) or if some network problem causes all clients to drop from the server (the "zero players connected" state at the root of many rare co-op bugs).

There's a reasonable workaround to this though: require a positive input to the spikeshooter, using a trigger_multiple from the region after the gate. Now we've changed the conditions to "no players before the gate, 1 or more after the gate".

The last thing to worry about is what happens if players die after you've fired the gate event. They will presumably respawn in the pre-gate area of the map, so you have to remember that you can't guarantee that players will remain trapped on the far side of the gate. This is especially important if you're locking an arena with a door - how will dead players rejoin the map? If your answer is that they can't, are you happy that the map will be impossible to complete if everyone dies? Or get disconnected by a network glitch? Don't worry unduly, but do try to bear these in mind. Good luck! 

Simplest solution to the problem at the end that I can imagine is to have a second, drop-down pathway that opens when the gate closes. Small, short & simple but enough to let players rejoin the ongoing fight. 

3 cheers for Khreathor and all the modeling help he gives me. 

I am seeing a lot of new users here. Both posting maps and questions. New blood is always good in the Quake scene. Glad to have you all. Stay... please!!! 

I now have beef with dumptruck for interrupting my round of cheers. 

EOM 

https://www.youtube.com/watch?v=Uy0QT4uy5KA 

G'day gentlemen, has anyone found all the secrets in skacky's Jam 9 map Chasing Promises? Stuck at 16/20 looking for book 2 of 2 and chasing naked statues :) 

....u there dude? Or anyone got an email addy?

https://www.twitch.tv/videos/223256760 1:19 for him. 

Lol, "It's got base and medieval, which is a sin against humanity." I literally almost spit out my coffee. Sounds like you're using the unreal soundtrack; awesome.

That map was actually cut short in its development by the jam deadline and in the final version the layout will make a lot more sense, with more secrets; and the grunts will be replaced with medieval archers so I will pray for absolution. 

Glad you saw it. I had a great time the first time, and a great time the second time. It is one of my favs, ever, I think - the vibe of this giant natural tunnel through a mountain, with this crazy temple complex spanning it....mmmmmm. I don't mind the archers and they would work well instead of grunts, as long as it's just them :P 

Has a map ever used a hotrod custom progsdat in which there was a super special teleporter setup that didn't notify the player with whimsical zinning sounds or fantastical particle displays as to be used to make faux non-eluci..illuci..non-euclidean structures? Also I once attempted to brush out a Möbius band but getting the bendy curve part required tolerances the program and I couldn't manage to produce. 

Don't think so, as to make it truly seamless (i.e. Unreal engine portals, or the... portals in Portal) aside from muting the teleport WHZIRRRIRIRIR you'd also have to disable the player's view being automatically centered when teleporting. Oh, and somehow keep their movement direction and position because normally no matter where they touch a teleport trigger, they get sent to the exact same point where the destination is, so basically remove or change everything that makes a teleporter work as a teleporter.