I noticed this issue first in the court yard of the moat house of TOEE and it became obvious in IWD mod. There were four orcs in my initial encounter in the orc cave of IWD. This should be an easy fight, right? Three downed, but the fourth orc, white circle, was in the fog of war. Don’t understand why the orc in fog of war joined the battle but never came to fight me. I guessed I needed to go for him. This is the issue NO.1. Monsters in fog of war joined the fight but never come at the players. A few steps ahead and we got two more orcs to slain. I don’t understand why these two orcs didn’t join the battel at the start since they were the same distance from me as the fourth one. Another three downed and I found out another orc, white circel, in fog of war joined the battle. And yes. I needed to bring the fight to him. A few steps and another orc came into sight. Another two. Another two. Another three. Finally, I killed 15 orcs instead of the original 4 I faced. But soon after the battle ended, before I can walk my party into the exit of the cave, another orc in the fog of war initial another fight. I guess I have to kill all the orc in the cave before I can go back to base.
Could be a temple+ issue, since I just fixed a bug that caused something that sounds similar (AI failed to pathfind when far away sometimes because of a path truncation error). A new release is around the corner, maybe it'll fix it.
Assuming you are using either the IWD mod version uploaded to www.modbd.com or the original demo posted on these boards with the patch 1 addon loaded too, (IE the fully up to date versions) then the issue must be Temple+, I certainly don't get this problem without Temple+, and regrettably haven't tested it enough with Temple+ to give a definitive answer.
I've never used Temple+ but I do occasionally see that monsters at the edge of FoW (or in the FoW) are sometimes in the battle. They do run in to the melee, or the engage via missile weapons or spells while remaining in the FoW, but I don't recall any of them just standing around in the battle. I don't recall getting these extremes cases that swapoer has shown in those pictures. Unfortunately it has been some number of weeks/months since I last played, so I will need to replay the game to confirm what I am seeing. And it has been even longer since I've played ToEE and KotB to see if it is just an issue to with the game engine, or something specific to the IWD conversion I just pretend that I am in their territory and so they don't have any FoW applied to them, and their eye-sight range is further than mine, so they can engage in a battle more remotely than me.
I played through the demo without Temple + pretty recently, and found much the same issues swapoer reports. Several fights would drag on as enemies that were not visible and did not approach the party kept the party going. I understand Allyx's intent in making the goblin fight an endurance run, and I don't have much problem with it (reminded me a bit of Hickory Branch) but the fight in the orc cave was pretty annoying.
Ok I just played through that. It seems that most of those who stayed in the fog are Archers. They don't have an "Approach" AI for when they can't attack it seems, so they just stand back waiting for you to come at them. (that probably happens in normal ToEE too). I did see some oddity with Orcs that were in the fog, and joined the initiative queue, but didn't actually enter combat mode... that may be unique to Temple+ though.
I've never used Temple+ and I certainly have Orc Archers in the cave firing at me when they are deep in FoW, and the Orc Shaman casting his spells, too. It hasn't really bothered me and I wasn't sure if this was something within the ToEE engine (as I don't play it often), so I've not previously mentioned this AI issue in the Orc Cave. I've not really seen it in other maps. For the Pass - I go one step at a time, and I don't usually have one long endless battle. I quite like the Pass.
It's a puzzler - do we want our archers having 'approach'? I can see that being reported as a bug if it is implemented. "And then this archer just came around the corner and ran right up to me!"
A heavy handed "approach" will certainly cause problems. For Temple+ I'm going to add an "Improve Position" command for archers, which will make the AI approach the minimum amount necessary to have LOS. For regular ToEE, if you care to do so you can use the "beacon object" trick, which I've discussed somewhere here with @marc1967 .
It would be cool if there was also a 'keep at range' option for archers to move away from targets, but keeping line of sight with the target then firing, so they can stay at range from the PC's longer, currently there is no option to do anything but approach, or stay put.
