V12 wrote in Tue Apr 13, 2021 8:45 am: This is clear evidence of the inefficiency somewhere in the FlightGear or generated OSM geometry or LOD management.
The issue with objects in the old OSM2City format is well understood
https://wiki.flightgear.org/OSM2City_1st_WorldbuildStuartB's work on WS3 version of roads should lead to the road object being moved to the better format.
Once all objects are converted, FG will end up with the fast version and the other sim will end up being slow..
V12 wrote in Fri Mar 26, 2021 5:56 pm:For example, P3D v4.5 and resource heavy FSL A320 with visibility forced to 320 km does not reach 10 GB on same flight at FL390.
The plane won't take up much RAM compared to environment/scenery so it doesn't matter for this exercise.
Like Hooray said, FG and P3d aren't doing the same thing. So it's hard to compare:
- Terrain - does P3d have as detailed an elevation & landclass mesh, or are mountains more rounded like at LOWI? P3D also likely doesn't have textures in memory for close up detail - because it doesn't do that level of detail.
- Clouds - FG has very detailed volumetric clouds that respect 3d stucture, that are simulated/tracked.
- Does P3D actually draw land far out as 250km, or does it hide it in a fog...
- You may be loading trees, buildings, roads, etc. at far larger distance (Lod:rough) than P3d does.
- FG can do trees at far higher (i.e. realistic or somewhat realistic) densities. Other sims can't (the new microsoft sim uses fewer trees and a 3d tree shape to increase cover which results in forests that look from above like cupcakes arranged on a tray). This also takes up some memory.
- FG flight was higher so it may have loaded more terrain even though the visibility limits were different (horizon distance goes up with h^0.5).
- You may have had OSM2City on objects
- WS 2.0 doesn't have a LoD system and loads the full resolution entire terrain mesh AIUI. However the memory usage is reasonable, as people post screenshots of ranges far higher than 250km like a good portion of the Earth with the Space Shuttle e.g. this old screenshot at FL3300 :
link. How much does FL3300 with draw distances like these take in P3D?
- As Hooray said WS3 will have a very powerful LoD algorithm, but FG can already do massive draw distances under 32 GB.
- As Hooray implied a memory leak could be contributing to RAM usage, on either FG or the other sim (it could be because of some codepath triggered by the specific craft).
Hooray wrote in Fri Mar 26, 2021 8:32 pm:To be honest, FlightGear has been lacking in many areas compared to commercial/proprietary products - however, given enough time, FlightGear also has been catching up with some of them (sooner or later). Often, it literally takes a while and features/components need to be reconsidered or even efforts started from scratch. Anyway, there are some examples where FlightGear has managed to acknowledge its strength and where it has come up with features that are empowering contributors, such as for example the property tree, XML, XML based FDMs, open 3D models, Nasal scripting, the effects system or the Canvas system.
Basically, it isn't realistic for FlightGear as a project to catch up with commercial projects in the core department - [..]
I agree entirely with the main point that FG's data driven approach is very helpful, and makes iteration faster even for people who compile from source as reloading is faster than even an incremental linking, people don't lose the train of thought while waiting/interacting with the compiler, and reloading means FG doesn't need to be restarted each time.
With regards to closed source commercial products: in an ideal world it's easy to imagine that the budgets would translate into better core in a lot of areas. Of course, the reality is quite different and FG's flight fundamentals are way ahead, and it is not the intent or vision of commercial management to catch up with FG.
A lot of the commercial sims historically have been from the game development side (Microsoft), and by companies who are listed in the stock exchange who additionally don't really care about simulation as their main activity. Then there are smaller studios like Laminar Research who are owned by people with an interest in flight, but get massively out-marketed and have to struggle. Until 2-3 years ago every other sim was 32 bit - then X-P 11 came out. X-P still uses a spherical earth model IIRC, none of the sims have a good a weather simulation, and the new MS sim and X-P only develop a runtime art based FDM so they aren't trying to be realistic. You've projects like P3D that have a limited FS-X license and mainly just allow people to replace parts of the engine while relying on the Lockheed Martin name, and FS-X derived projects with the other half owned by companies with no interest in being realistic.
I looked into the new Microsoft sim because of the initial hype videos and this is what I found (quick google/bookmarks from back then): The new Microsoft sim is made by a game studio - with the usual thing where they built an openworld game engine (which only supports DX11 [
link]) and then realized it could be used to render a flightsim - but unlike Outerra they didn't give up after realising a sim was more than a game engine. They just bought the rights and like code to the early access version iteration of FS-X that Dovetail, a company formed by train-sim modders, was converting to 64 bit [
link]. As the new MS sim is made by a game studio [
link] and obviously they had no prior interest in flightsim [[url=https://www.youtube.com/watch?v=FDTT3oxArLI&t=251s
]link[/url]]. Microsoft's interest is in a console exclusive in their competition against Sony's console, so they are fine as long as they advertise massively and get some return. The game studio seems to have kept the game engine cloud plugin Dovetail was using, which only has clouds that look like porridge at close range and turn milky when flying through them, and they just took the fastest route to texturing and populating the world using existing photo maps and AI. The flight dynamics of both X-P and MS sim use runtime flight models to make it easier for art centered teams to release DLC, so they aren't really aiming for realism. That's also the reason why available commercial sims don't even have a decent weather simulation (XP would no doubt like one, but they have other priorities). The only reason the new MS sim had a non-trivial live weather implementation is because the people at the live weather service at least understood and saw possibilities.
I was reminded of this fact by the PR in the interviews for the new sim around launch: Part of the issue is that the game industry that much of these sims seem to come from, appear to massively underpay professionals (software engineers:
link), as well as every other area [
link]. This prevents software/hardware engineers and scientists with an interest or expertise relevant to flight simulation from being hired by management - at standard wages anyway. The usual games management strategy seems to be throw money at advertising, with one game in this list having a marketing budget of 4x the dev budget
:
link. It's easier than arranging all the R&D and nurturing teams. I was reminded of this point with the PR that //continually// mentioned one of the leads [
1] went to a university that had a french name with applied mathematics in it [
link] - trying to make it sound like the team had a scientist/engineer with a background in hardware as people would expect at least one in a sim project (look at XP or DCS) - it turned out to be just a quirk of the french education system and the maths being referred to was school maths. He turned out to be a (software) game developer before this project as expected, albeit one with an interest in ground vehicles.
So sadly you have a lot of bigger commercial projects which have no interest in being realistic, while the smaller privately owned companies are out marketed, too small, and also focusing on revenue. These projects will mainly be somewhat strong in core areas where they can plug-in existing game tools or re-use parts of their game engines (usually related to graphics), and feed it with art they can buy/make.
(You would know much this. I'm just making the general point that FG does have realism that other sims don't have, and have no real intention of ever achieving - but comparisons seem to be one way.)
Kind regards