So I haven't posted on this forum since around Halo 3. but with Halo 4 I've been getting back into forging, and I've been working on a map with hopes of posting it on here and ran into a god awful bug that I need to warn you folks of! The only cause I can discern for this bug is forging with other people on your map, as that's when it happened to me. SO, on to the bug itself: I launched my map (after finishing most of the building on it, with the intention of showing it to a friend, and upon entering the map noticed that every single object was slightly tilted, I thought it was odd, and went to edit coordinates to see what had happened and every single object had a +1 to it's Yaw value. Every object, I tried to quit and see if it was an odd load or something, but it saved the progress, and now I have to tediously go to every object and fix that 1 degree yaw angle or I will go insane. Unfortunately the only way I can think to replicate this is to launch a game of forge with your map, in a group. I don't want to test that theory, (in too much of a rage as to how much 1 degree yaw changes I'm going to have to make, so... yeah. Sorry for any grammatical or spelling errors, I'm just super pissed off, and a little tired at the moment, but figured I would warn you all of this before you too fell victim to it.
It isn't isolated to multiplayer forging. I forged for a while, saved, ended the game and came back a few minutes later to it all out of whack. It happened in Reach too, but on the Y axis.
It happens when you load a forge session with another player in the game, and sometimes when another player joins you. If you saved your map as you went, which you should always do, and don't save after the bug occurs, it isn't a significant problem. Just be smart about saves and other players until they fix it.
That's the thing: I didn't save after I noticed it, and it saved 'automagically' and I had to go in and edit everything by hand.
I tested this bug a bit tonight. I had Shoe join my forge session, at which point he noted that all the pieces shifted on his screen, which I confirmed when he walked over the bump at the lip of a ramp. However, from my point of view everything was fine, and I was able to walk over the same ramp with no problems, which was also confirmed in the same way by Shoe. This leads me to believe that the glitched object rotation is host-dependent, since there was no host migration when Shoe joined (meaning I was still host, and because noting had changed for me). So, assuming that the glitched rotation is linked to being host or not, my conclusion is that any non-host player who loads the map will see the glitch, including the original host in the event of a host switch (because that player has to load the map again). The question is then whether or not (or under what circumstances) the glitched rotation will affect saving the map. I tested this by saving my map with Shoe still in the game, and with the glitched pieces still visible on his screen. I loaded it up in a custom game, and lo and behold the pieces were in their correct orientations on both our screens. Once again, this leads me to believe that only what the host sees matters. Other players joining a forge session in progress doesn't always mean you have to quit without saving, it's only a problem if there's a host migration.
I've gotten glitch rotation without having shown anyone my map though. Like I said, I forged, ended the game, came back (my party is invite only, mind), started it up, and the pieces were askew.
Had a similar issue to this, but with object properties instead. Didn't know if it was MP dependent or just in general. Made a thread about it. Details there.