http://www.youtube.com/watch?v=ZGtHa0Poroo

At 14 seconds, he turns around and fires the orange portal onto the ground there. If you simply stand on the other side of where the red portal is in that video and fire it, when you jump into the blue one you'll come out facing the wall instead of the other portal.

So the red one has to face the blue one and the blue one has to face the red one, like this:

x = you
| = ledge
(b) = blue portal
(r) = red portal
^ = wall above corridor
<- and -> = direction player is facing when portal was fired onto ground.

(b) <- |x -> (r)^

That way, when you (x) stand on the ledge (|) and jump into (b), you'll come out of (r) heading toward (b) again so you can keep looping yourself and gaining speed.

However, if you make the portals face like this (e.g. shoot them in the same direction on the floor instead of making them face opposite directions like the first example), when you jump into (b) and come out of (r), you'll be facing the opposite direction of (b) and you'll hit the wall right above the corridor you originally came out of from the elevator.

(b) <- |x (r)^ <-

Why does it work like this? It's so agitating and no matter how much I think about it I can't make ANY sense out of it.

It works exactly how you'd think it should work... at least it works the exact same way as if the portals were fired at walls instead of the floor.

Think of it as firing a portal at a surface so that the top of the portal is always at the top of the screen. This is easy to understand then fired at walls, but a little less clear when on ceilings or floors.

In that video, he fired at the floor below the ledge, so that the "top" of the portal pointed away from the ledge/wall. When he turned around an fired at the floor on the ledge, the "top" of the new portal was also pointed away from the ledge.

The top of the blue portal should correspond to the top of the orange one... and it does. Simples.

compherm wrote:
It works exactly how you'd think it should work

That's the thing. Sometimes it doesn't work properly and you'll assume you lined up your portals properly and fired them in the right directions to go where you want to go, only to go in one and come out the other with your face against a wall. It's agitating and it's not documented anywhere how this aspect of portals is supposed to work.

Then you clearly aren't thinking with portals. They always work... it's not random.

m1dy wrote:
It's agitating and it's not documented anywhere how this aspect of portals is supposed to work.

I don't think it needs to be documented. The top of the blue corresponds to the top of the orange. Simple as.

This might look tl;dr, but give my post a chance and I guarantee you'll learn something new and extremely helpful about Portal, that is of course unless you've already discovered it yourself.

You're misunderstanding what I'm saying entirely.

x = you
(b) = blue portal
(r) = red portal
< / > = top of portal

First, let's say you're standing in a square room, completely flat, no objects, ALL portals are placed on the floor.

Now, let's say you want to jump into the blue portal, come out of the red one and then go back into the blue one again to create a loop and build speed and height this way:

(b)x(r)

To make the above diagram work, you have to fire the portals facing certain directions, you then jump into the blue one:

<(b)x(r)>

Alright, so, that works properly, but it only works properly because you lined them up that way, now try this:

(b)>x<(r)

Now you've fired them in the opposite directions, if you jump into (b), look straight down and come up and out of (r), you're going to be facing the opposite direction of (b) and you're now going in the opposite direction of the portals you've made.

This is exactly what I was talking about, it's never documented ANYWHERE that turning 180 degrees and firing a portal in a different direction will make you face a different direction when coming out of it.

If you still can't understand, watch the video I provided above. What does that very first line of text say? It says "PORTAL PLACEMENT IS IMPORTANT", that statement couldn't be more true. If you walk into that room and fire a portal where is red one is from the opposite direction then jump over it and fire a blue one and then jump into the blue one you'll come out of the red one and be facing the wall - the wrong direction. Thus you have to stand on the ledge by the blue one and "turn" the portal around by shooting it again. The only reason I know they work this way is because I practically spent an hour in-game experimenting with how the positioning of portals and the side of which you fire portals affects your orientation when you come out of said portals. Also, I never said anything was random.

compherm wrote:
I don't think it needs to be documented. The top of the blue corresponds to the top of the orange.

Now see, that's TRUE, but you're forgetting that I was originally (now enlightened thanks to experimenting a lot) questioning the placement of portals, not how they work. And you're forgetting or are unaware of the most important part; the top of a portal can change entirely when they're placed on the floor from a different direction. Fire a portal on the ground from Side A, walk past it to side B and fire it again in the same area and the top of the portal is now facing a completely different direction (this being my original lack of knowledge).

EDIT: Something I discovered during my experiments: Take a close look at your portals next time you're in-game, see how one side (top and bottom, not right and left) of the portal is brighter or looks as if its "burning brighter" than the other side? That's the side of which the portal was fired, this only applies to portals on the ground and it's the exact opposite for portals on the ceiling, the top will be "burning" instead of the bottom, but the orientation is the opposite. So this means if you're trying to get over a wall by falling into floor portals, you can make it a lot easier by making the "brighter" side of the portal face your objective, then when you go into the other portal facing straight down, you'll come out of your exit portal facing the direction you wanted to face in the first place, all you have to do is hold W and move your mouse down a bit so you can see.

Portal may appear simple, but it's probably one of the most deep games ever made when it comes to its inner workings. I've been a huge fan of Valve's creations and playing them on Steam ever since the very beginning, and I can say there are so many undocumented variables that come into play with portals, I'm basically just trying to find and understand all of them and master this game. Portal is NOT as simple as you think it is. Sure, you can go through the campaign successfully without knowing any of the stuff I've shared with you here with the whole "THING GO IN BLUE PORTAL, THING COME OUT RED PORTAL. DERP." mindset, but you'll struggle and struggle and struggle with advanced maps and least portals/steps/time challenges.

Use MS Paint to draw what the hell you're talking about, because a bunch of <(b)x(r)> really isn't helping anyone.

My original post and the video explained it just fine, you're reading too fast or not at all. Watch that video, he turns around and makes the red portal, if he made it from the other side (the entrance of that chamber), going into the blue portal would make him go in the wrong direction. This is the fault of the guys who made the map, not portal, but it's still present and most people don't notice it.

Also, the "problem" has been solved already and I fully understand the functionality of portals on various types of surfaces and why they function that way on said surfaces. This was a help thread, help is no longer needed. If you REALLY can't understand it then go in-game and experiment with shooting portals on the floor, then turning around 180 degrees and shooting them there again, you'll be facing a different direction if you go back to the other side and jump in that portal.

tl;dr the position of which portals are shot from influences which direction you come out of them, period.

m1dy wrote:
tl;dr the position of which portals are shot from influences which direction you come out of them, period.

I think this is why we are confused. Most of us have found this out already during our own experiments.

How one can be confused about something they're already fully aware of boggles my mind but that's besides the point, this was originally a help thread I suppose you could say, and the issue's been solved, or understood rather.

I think the more simple answer is that, yes most people recognize this anomaly and just roll with it. If there is a "reason" for it, I'd say it's because "Portals" were new and aren't an exact science, so there is some physics weirdness that happens with them. There are a lot of well documented glitches with Portals, I think this is just another one of them.

So basically what you're saying is that when you shoot a portal on the floor looking one way, the top is facing one direction, but when you shoot it looking another way, its facing a different direction?

If thats the case then what's so confusing? I discovered this after about two custom maps and haven't really thought of it since...

Has OP played portal?

Play the game, then you will understand portals!