While what “broke” invisibility is mostly “fixed”, I thought I’d take the opportunity to explain what happened, as it has to do with a part of DDO most people are not very familiar with. This actually includes me, but I’m going to tackle it anyways and try later to check it against numerous posts made in the DDO forums by experts on the topic.
At the time of this post, we are using Update 18 Patch 2 (or just update 18.2). At some point before this time, a change was made to stealth mechanics that “broke invisibility”. What actually was broken was how stealth mechanics worked. Where many people had found ways of completing some quests quickly by bypassing fights using invisibility on the whole party, these strategies no longer worked. The obvious assumption was that invisibility was broken and that monsters could now “see” you, even if you were invisible. This however was not really the case. The break in the stealth mechanics had caught the invisible by surprise.
Stealth mechanics is based on two skill pairs, Spot/Hide and Listen/Move Silently. Invisibility only helps out with the Spot/Hide pair. Most users of invisibility were unaware or had forgotten completely about Listen/Move Silently. In DDO when you activate the Sneak feat, you start using your Hide and Move Silently skills. Enemies that are near you get to make rolls on their Spot and Listen skills to try to detect you. This also works in reverse. There are enemies that actually do not spawn on top of you all of a sudden. They are merely stealthed and undetected. When they attack you, they break stealth and seem to suddenly appear from nowhere.
If you have a sufficiently high Spot skill, you can see the outline of enemies that are stealthed. You can target and attack them, thus breaking their stealth. The other detection method is via the Listen skill. If you have a high enough Listen skill, stealthed enemies will make little red echo marks at their feet when they move. So as said in the last paragraph, it works both ways. Enemies make both Spot and Listen checks. While a Spot check can be foiled by invisibility, a Listen check cannot. If you are invisible, you can still be located by a Listen check, and it happens a lot if you are not sneaking.
What went wrong a while ago was that what followed a successful Listen check, got broken in several ways. Noise in DDO can actually be used to distract an enemy. Shooting at a wall will cause the enemy to investigate the noise, provided they do not see you shoot. The same is done with a Listen check when you are sufficiently far enough away from the enemy. It goes into a searching mode to try and acquire you. If it does acquire, it can then track you and will try to attack you. One problem that happened when the stealth mechanics were broken was that enemies skipped over the search mode and went straight to acquire, even if you were far enough away. This led players who were invisible to claim that the monsters were “seeing them”, and that invisibility was broken. They actually hadn’t been seen, just heard. The broken “skip to acquire” stealth mechanic just made enemies run straight to and follow the invisible players. Where before, enemies would usually start looking around, and the players would leave the area before acquisition.
Another thing that went wrong with the stealth mechanics was enemy accuracy. Normally enemies would make a reasonable effort to hit an enemy they hear close by. Unfortunately the behavior for ranged enemies became 100% accuracy. Again making the impression on invisible players that they were being “seen”.
Also helping perpetuate the myth of “invisibility is broken” is Update 17, The Return to Gianthold (often written as just epic GH). When Gianthold got an epic version, most giants in it got a permanent buff. It was See Invisibility. The buff has existed for a long time as a level 2 Wizard/Sorcerer or level 3 Bard spell. But epic giants have it permanently. If you target them and examine them (by default the ‘Z’ key), you can mouse over the icons and you will find it. I imagine before any update, developers revisit at least a few quests, a raid and/or challenges and tweak them a little. It is not unreasonable to assume that any boss, mini-boss or epic enemy who does not currently have See Invisibility, could acquire it during any update. So for enemies that have the See Invisibility buff, sneaking might still make them fail their Listen check. But invisibility will not help with their Spot check. If you don’t have a good Hide skill, then sneaking while invisible is almost like walking around normally.
But even if you don’t have invisibility available to you, sneaking can still work for you. Even if you don’t have any Hide or Move Silently skills, my experience tells me that sneaking can still keep you undetected by enemies that are fairly distant, or have very low Spot and/or Listen skills. I have actually seen a fighter with no skills sneak through the dreaded level 2 quest, Stealthy Repossession and finish it. He kept a large distance between himself and the Kobold Prophets and was extremely careful to break stealth (opening doors, pulling levers, etc), only when no enemy was looking his way. I don’t recall, but I imagine this was only done on the normal setting. But it still applies. You can peek around a corner or over a ridge while sneaking. If no enemy is close, it probably won’t see you. Even if you don’t have the skills to avoid detection.