A Basic description of the visibility problem for distant aircraft in the il2 sim series:
I: For those who havnt yet seen how the LoD (level of detail) models work in il2
first, you have the close up detailed external view of an aircraft, it shows it in all its glory but also takes a huge amount of cpu/gpu power to display.
- this detailed visual representation will stay the same up to a certain distance (a 100 meters + ?) where the aircraft just becomes smaller and more distant
second, at some fixed distance from the viewer the more distant aircraft will then transition to a LoD model which keeps the rough shape of the aircraft, but gives much less visual detailed information (since you cant see it anyway, and would be a waste of cpu/gpu power to keep drawing it)required)
third, at an even further away distance this previous LoD model will transition to another even smaller and more rudimentary one, it will only have the rough outline of the aircraft it represent (single or multi engine etc)
fourth, at the furthest away distance (usually somewhere between 1000 and 5000 meters depending on how big the aircraft is) that last LoD model will transition to the "il2 Dot". when you are flying as a fighter pilot and expect other enemy fighters in your area, being able to see these "Dot's" from a realistic real life distance is extremely important. eg, if in real life you might be able to spot (and then track) a moving dot somewhere 2000 meters below you, you'd hope this would be accurately represented in the il2 sim series (but this sadly is not the case up untill now)
these 3 shots show the 3 LoD models for the p40 in il2 (for some reason the animated gif wont work on this forum)
the problem this currently creates, aside from some of the errors in some of the LoD models themselves (like the 2e LoD model of the seafire having no wings, making it much harder to detect), is that these smaller LoD models are just little clusters of flat little 2D pixles sliding over a 2 dimensional flat image of the distant terrain scenery that your pc struggles to make look like a real landscape
so problem 1: that distant little p40 might well be the right size, but on computer screens it is MUCH harder to spot (and keep track of) then a real life 3 dimensional little object standing out against the background more (the human eye through millions of years of evolution is very good at tracking those real life little objects in the distance)
the good news: after repeated previous "complaints" in elaborate "discussion threads" on the main flightsim forums. oleg does recognize this problem and now hopefully has implemented the "little 3D blob" method to make them stand out a bit more (the little blob takes much less computing power, and visually more closely represents what the human eye can detect). this new implementation by oleg was visible in one of his early bomber formation video's
problem 2: for the smaller LoD models, the little cluster of pixels that roughly keeps the shape of the intended aircraft, ONLY DOES SO FROM CERTAIN ANGLES, ie it depends what part of the aircraft you are looking at. from many viewpoints this cluster of pixels will fragment and break up, completely loosing the shape of any aircraft it might have been, making it 50x harder to keep track of !
as an example: this is a distant view of the smallest LoD model for the earlier p40 example
now if you look at a screenshot of a flight of four i-16's heading in your direction (from a similar distance as the last smalles p40 LoD model in the previous illustration), you can clearly see that
only one of them looks vaguely like a "plane" (yet it is a formation of 4 planes flying together), the others which are immediatly adjecent to the first one are just seen from a slightly different angle, but have now just
become an erratic irregular group of pixels, AND those drawings
constantly change shape depending on the view angle !
so instead of seeing a solid "aircraft looking pixel group" coming your way, you catch intermittent glimpses of a jumbled shape of loose pixels coming your way instead (and this is against open blue sky).
Now if you put this in front of the complex shaped and colored "ground terrain" textured background,
the human eye simply cannot track this irregular moving cluster of loose single pixels, due to the lack of well defined shape to visually "lock on". You can intermittently reacquire the target when it changes to something more visible as it comes closer and transitions to a larger LOD's, but in a combat situation where both aircraft are doing 300 km/hr and are rapidly closing (or he is trying to sneak up on you) this is not "simulating" what a real pilot would/could see, and therefore doesnt allow realistic combat engagements because you situational awareness bubble has shrunk to 30% of what it should be.
the good news is Oleg seems to understand this problem, and the fact in il2-1946 the smaller LoD models still create "invisible aircraft" (at distances you would normally be able to spot them in real life), and by all early indications of some of the preview videos we have seen so far, these distant small LoD models are now represented as little "3D bubbles" (like a water droplet). this means the object keeps its volume and visibility much more, and is an elegant solution to trying to represent a distant aircraft on current 2D pc display technology (which has significant limitations in representing distant 3 dimensional objects).
II: When the smallest LoD model transitions to the "il2 dot"
this is an example of the "3e LoD to Dot transition point", when the il2 sim series represents very distant small aircraft shapes with a "dot" (either 4 pixel clump, or 2 pixel clump)
for the b17 and its wide wingspan, it transitions to a "4 pixel dot" at around 5 km (for a small single engine fighter this lod to dot transition point is much closer, somewhere between 1000 and 2000 meters). as you can see from the illustration, one moment you have a vague representation of an aircraft shape, the next it is just a little dot (this is done to save cpu/gpu power)
- the problem we have is that these 4 (or 2, or 1) pixels might well represent the right size for the distant aircraft, but as illustrated earlier for the smallest LoD models in a 2011 pc game these 4, 2, or 1 dot sizes are not visually identified to the same extent on a pc monitor as they would be visible in real life.
so these smallest pixel clumps DO need an enhanced visibility feature as well to make them stand out more (and it needs to be a solution that is equally valid for 6 or 8 bit monitors, so we dont have a repeat of the MAJOR problem this created in il2)
For the il2 "dot visibility" however there are no indications this has been solved for BoB-SoW !! we now have (in 4.08 ) a "4 pixel dot" representing a very distant aircraft (that has become smaller then the 3e LoD model), and the game keeps this 4 pixel dot as the smallest representation of the distant aircraft (untill it suddenly completely vanishes at a specific distance). some indications are that in 4.09 this 4 pixel dot was now drawn even smaller as a 2 pixel dot, and from one of luthier's recent comments in BoB-SoW the game engine will even give further more distant visibility and at greatest distances an aircraft will be represented by a single pixel
note: this situation is not helped by the fact that not many il2 users know exactly what a "real life distant aircraft" should look like when seen from a ww2 fighter plane cockpit, and some well meaning (but ignorant) posters will raise unrelated reasons like "but the plane has camouflage paint so you cant see it"
note 2: any discussion on this topic with il2 users is further complicated by the fact that 6 bit monitor users have a much less severe dot spotting problem, because of the inferiour ability of their monitors to represent grey shades, these grey/black dots stand out much more and they might be able to see them 2 or 3x better then most other users (an additional factor is that many pc users dont have callibrated monitors, and il2 players dont use a standardized amount of AA and AF on their gfx cards). so not all il2 users are aware of how severe this problem is.
conclusion: some in game enhancements need to be used to make distant aircraft (and ground targets) stand out more so they are visible (and able to be tracked) from similar distances as they were for real life ww2 pilots (and this is needed for both distant small LoD models and the "il2 dots"). currently il2 has 30% of this visibility we should have, and we fly around in a myopic mini bubble of visibility which completely distorts what your normal situational awareness should be. this problem is the most significant issue in what makes the il2 series a "simulator", and needs to be addressed as a matter of priority for BoB-SoW (and by some indications oleg has now partially addressed this)