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Guest Zevious Zoquis

One thing I have never thought about since now......

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In FS, when you fly,...is the aircraft moving over/under the scenery/sky (as in real life), or is the scenery/sky moving under/over the aircraft?Oh yes,..and it is a serious question....because I sure don

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Staffan,Doesn't that depend on your point of view (as in real life)? ;-)I know Einstein had some ideas about this subject.Cheers,

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Guest BOPrey

When you walk, is the floor moving backward or you are moving forward? The correct answer. If the point of reference is part of my body, the floor is moving backward. If the point of reference is another object other than myself, the anwser depends on the motion of that object in relation to the floor. LoL.

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Thought I said it was a serious question...;-)Really,...do anyone know if MS programmed the scenery to move or the aircraft?And yes, I think it matters...because the answer can probably explain alot of performance problems.http://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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Guest 2002cbr600f4i

Well, I'm assuming they did it the same way that all FPS games do it - there is a world (3d model space) and then the user has a viewport on that world (whereever you are looking). All the calculations are done based on your viewport + movement and the world is then updated.So, I'd say it's "the scenery 'moves' under your aircraft."--2002cbr600f4i

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>Well, I'm assuming they did it the same way that all FPS>games do it - there is a world (3d model space) and then the>user has a viewport on that world (whereever you are looking).>All the calculations are done based on your viewport +>movement and the world is then updated.>>So, I'd say it's "the scenery 'moves' under your aircraft.">>--2002cbr600f4iOk, if it in fact is what you say,...it is very much as I thought it was.Kind of strange though to think that the more you give thrust, the faster the scenery moves and not the plane. :-lolhttp://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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Guest FxF3

I did a lot of modding with CFS3. In that sim the world revoled around you.:-) Your plane was stationary while the ground and sky moved.Who knows about FSX it seems the ShadersHLSL have alot to do with what we see in FSX.

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Guest allcott

I suspect that flight sims in general do it BOTH ways. The Fixed Point of Relativity (FPR) is ALWAYS defined in relation to the aircraft model, but the interraction of that point is fixed in a non-definitive sense, to allow for things like the rarely used `next aircraft` viewpoint. So it cannot be immutably `fixed`.So the answer is, in a dimensional sense that both move. Each in relation to a fixed point, but also in relation to each other.If you think of the SuperMarionation series in the Sixties - Gerry Anderson and Thunderbirds, Stingray, Captain Scsrlet and so on, they had moving models of the aircraft, ships and cars, and a moving background. Each had its strengths and weaknesses and was used at different times for different effects or both together. The result had to be convincing, not the obeying of physical laws to portray that result.In FS you also have to bear in mind that even the intangibles must have `representation` in the global universe - things like the weather and the sound must also have a point of relativity. We do know that the cylindrical world of FS2004 has been replaced in FSX by a much closer to global world so it is feasible that all points might now be relative to a fixed point in space - the centre of the virtual world. But if that were the case, we'd have virtual submarines and virtual fish as the sub-surface could be modelled. Instead we still have a `quilt` of mesh, landclass and texture, but not the `bed` underneath. Thought of like that, a Fixed Point of Relativity for the `universe` would serve no useful purpose as the construct of the inter-dependance between `moving` model and `moving` ground would require more physical calculation than a network of Crays could handle. The relationship is probably mostly the aircraft moving over the ground, but with the option to move the ground around the aircraft when the calculations demand it. I assume from my very limited knowledge of mesh that there are no independent or relational variables in the definition of the location of the points, they are fixed arithmetical calculations? ut in relation to what?Good question. :)Allcott

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Hi, PICs. Some one said: ====Kind of strange though to think that the more you give thrust,==the faster the scenery moves and not the plane. Wellll. . .1= Be in a plane, and fly it safe slow speed.2= Go in spot view, (the flexible one), where the point of view rolls slowly arond the plane.3= Now, push it fastly to full throttle, and seethe plane going away a little bit, before you "catch up" with it. Try it also, looking to the plane from a 0300or 0900 point of view. Left or right views. THE PLANE accelerates, and YOU acceleratea liiiiiiiiiiittle after that. . . Right ?4= Now do sharp truns. . .5= Do it all with **stiff** point of view. You will not "feel" the changes in speed. . .Blue skies.

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Guest allcott

Nope, that's purely viewpoint artifice. The important part is that the relative view angle stays pretty much on the same spot on the plane as you rotate around, up and over or to and fro.Allcott

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Guest Jimbofly

I hate to say it but you're quite wrong. It makes no difference whatsoever.As your aircraft moves, your viewpoint changes, so the scenery is updated to reflect your new position. That's the only way it can work and the only way it has always worked for all 3d games.James

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>I suspect that flight sims in general do it BOTH ways. The>Fixed Point of Relativity (FPR) is ALWAYS defined in relation>to the aircraft model, but the interraction of that point is>fixed in a non-definitive sense, to allow for things like the>rarely used `next aircraft` viewpoint. So it cannot be>immutably `fixed`.>>So the answer is, in a dimensional sense that both move. Each>in relation to a fixed point, but also in relation to each>other.>>If you think of the SuperMarionation series in the Sixties ->Gerry Anderson and Thunderbirds, Stingray, Captain Scsrlet and>so on, they had moving models of the aircraft, ships and cars,>and a moving background. Each had its strengths and weaknesses>and was used at different times for different effects or both>together. The result had to be convincing, not the obeying of>physical laws to portray that result.>>In FS you also have to bear in mind that even the intangibles>must have `representation` in the global universe - things>like the weather and the sound must also have a point of>relativity. We do know that the cylindrical world of FS2004>has been replaced in FSX by a much closer to global world so>it is feasible that all points might now be relative to a>fixed point in space - the centre of the virtual world. But if>that were the case, we'd have virtual submarines and virtual>fish as the sub-surface could be modelled. Instead we still>have a `quilt` of mesh, landclass and texture, but not the>`bed` underneath. Thought of like that, a Fixed Point of>Relativity for the `universe` would serve no useful purpose as>the construct of the inter-dependance between `moving` model>and `moving` ground would require more physical calculation>than a network of Crays could handle. The relationship is>probably mostly the aircraft moving over the ground, but with>the option to move the ground around the aircraft when the>calculations demand it. >>I assume from my very limited knowledge of mesh that there are>no independent or relational variables in the definition of>the location of the points, they are fixed arithmetical>calculations? ut in relation to what?>>Good question. :)>>>>>>AllcottHi Alcott,Interesting points there.So that means that the flight carecaristics in the FDE, practically determs how the world around you behaves....and not the aircraft? :-hmmmhttp://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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>I fail to see the difference.>Its quite easy,...for me it is a huge difference if I am infact tweaking the aircraft or the world around me when I edit the .AIR or Aircraft.CFG files.;-)It can also give some answers regarding the neverending performance issues with the sim.http://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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Guest Calb

Extactly James.A few years ago, my wife thought, since I seemed to be having so much fun, she'd have me teach her to fly FS. Since I have nearly 1000 hrs R/L experience and she's had her hands on the controls of a C172 many times, I figured I could offer insights that the average simmer wouldn't know about and it would be fairly easy.Alas, it didn't work.....not even close! It totally baffled me at first. If I asked her to make a left turn, she'd move the stick right!!! To descend, she'd move the stick back. I was dumbfounded because she is a very good driver and has no trouble with coordination or any of the things that contribute to driving. Then it dawned on me. I asked her, "to you, which is moving, you or the scenery". Her response was immediate, "the scenery, of course". No wonder!!Our attempts to "convert" her to a pilot's out-the-front-window perspective was unsuccessful and she finally gave up. No matter how much she tried, she could not get past the idea she was stationary and the scenery is moving.That's one of the biggest advantages a real pilot has over the non-pilot in FS. We see it as you and your monitor are moving and everything else is stationary. I'm sure that's the "immersion factor" the developers want the user to experience. After all, that's whats realistic, at least in my view.CalCYXX

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Guest Jimbofly

OK, here's how it works:The FDE determines how the aircraft's speed, attitude, heading, and altitude are affected. When the sim performs a calculation based on existing conditions and pilot input, the aircraft's position relative to the FS world changes. This new position is calculated and once that's done the world in the monitor updates to reflect that change.And there is ABSOLUTELY NO IMPACT to performance. The FDE calculations aren't done on planet Earth, they are done on the aircraft. The view outside the window simply reflects what you are supposed to see when your position and attitude RELATIVE to the world changes.Please don't purport to know why performance is affected. It's not.James

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>Extactly James.>>A few years ago, my wife thought, since I seemed to be having>so much fun, she'd have me teach her to fly FS. Since I have>nearly 1000 hrs R/L experience and she's had her hands on the>controls of a C172 many times, I figured I could offer>insights that the average simmer wouldn't know about and it>would be fairly easy.>>Alas, it didn't work.....not even close! It totally baffled me>at first. If I asked her to make a left turn, she'd move the>stick right!!! To descend, she'd move the stick back. I was>dumbfounded because she is a very good driver and has no>trouble with coordination or any of the things that contribute>to driving. Then it dawned on me. I asked her, "to you, which>is moving, you or the scenery". Her response was immediate,>"the scenery, of course". No wonder!!>>Our attempts to "convert" her to a pilot's>out-the-front-window perspective was unsuccessful and she>finally gave up. No matter how much she tried, she could not>get past the idea she was stationary and the scenery is>moving.>>That's one of the biggest advantages a real pilot has over the>non-pilot in FS. We see it as you and your monitor are moving>and everything else is stationary. I'm sure that's the>"immersion factor" the developers want the user to experience.>After all, that's whats realistic, at least in my view.>>Cal>CYXX>Interesting! ... never for one second in my many years of FS flying have I thought I was stationary and the scenery was moving!I guess I must have the immersion factor! :-jumpy

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A few years ago, my wife thought, since I seemed to be having so much fun, she'd have me teach her to fly FS. Since I have nearly 1000 hrs R/L experience and she's had her hands on the controls of a C172 many times, I figured I could offer insights that the average simmer wouldn't know about and it would be fairly easy.Alas, it didn't work.....not even close!This happened to me a few years back when I was showing Quake to my uncle, he was completely disorientated by the mouse view movement and couldn't grasp the idea that the mouse movement was the head/body movement of the character. Couple this together with the forward, back and side step... well let's just leave it there. ;)

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Guest Zevious Zoquis

for me there is no difference since the computer isn't actually moving a "world" or a "plane." It's moving bits in virtual space. As Jimbofly already points out, the way it works is you are at location X,Y,Z and facing direction W and the computer determines what you can see from that point looking in that direction. When your coordinates change, the sim calculates a new view. The FDE and AIR files are the "rules" controlling how you can change those coordinates. What you are talking about is closer to philosophy than comp sci and has no bearing on performance.

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>for me there is no difference since the computer isn't>actually moving a "world" or a "plane." It's moving bits in>virtual space. As Jimbofly already points out, the way it>works is you are at location X,Y,Z and facing direction W and>the computer determines what you can see from that point>looking in that direction. When your coordinates change, the>sim calculates a new view. The FDE and AIR files are the>"rules" controlling how you can change those coordinates. >What you are talking about is closer to philosophy than comp>sci and has no bearing on performance.>I understand your point of view. But for me it is quite an interesting subject, since I have always thought that when I push the throttles, it is infact the plane that moves, and not the scenery.If we for a second speculate in how the sim should be if infact it was the plane that moves, and the scenery was stationary.....well...to me that should mean much less processor load, since the simulator engine should not have to work that much....moving the whole world...:-hahhttp://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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Guest Zevious Zoquis

It's not a world. It's a virtual world. It doesn't actually exist. The computer doesn't consider anything beyond your line of sight (in so far as visual rendering is concerned.) Whether you want to see it as the plane moving around the world or the world around the plane doesn't change the calculations the cpu has to make at all. It's the same thing. You are here, here is what you can see from here. Ah, now you're here, and here is what you can see from here.

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Guest BOPrey

Why on earth would you think there is a performance issue if it is done one way or the other?Two ways you can do this. When the plane moves, you change the coordinate of the plane, and the rest remain the same. This is how it works in the real world and how most people will do it; even for none programmer. I am afraid that in the simulation world (at least in flight sim), the sun still revolves around the earth. The second way, don't change the plane's coordinate, but move every other object backward. This does seem to take a lot of CPU cycles. However, people are not stupid. Programmers would just use a single variable to keep track of how much the scenery has moved. When it comes to implementation, people will quickly realize it is same as method number one.

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Well, that is your theory, and ofcourse I tend to not agree with you. :-)Lets think from a "10 year old" perspective for a sec.If we play with the though that we simulate a part of land , like in a movie setup, and place it on lets say 20 trucks. To move that piece of land take a lot of more horsepower to move than if only moving a Cessna....or?Instead of mass (lbs/kg) in real life, the sim loads a whole bunch of BGL and BMP texture files.http://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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Staffan, what happens when you slew? The scenery updates depending on the new location. What Jimbofly wrote is right (for once). The position of the plane is recalculated on each render and the scenery updates. Its that simple - but this aint going to help you fix any performance problem now is it.

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>Its that simple - but this>aint going to help you fix any performance problem now is it.Ofcourse not. :-)I am only trying to after 20 years of simming, trying to accept the fact that it is the scenery that moves, and not the plane. :-hahhttp://www.scandicair.com/images/sa_banner.gifFSX..:-hmmm...nah.. Still happy without it!! :-hahMy specs are:Dell Dimension 4600 P4/2.8 at 3.0 Ghz1024 Mb DDR333 Dual channel memory (2x256,1x512)256 Mb ATI Radeon X850 Pro ViVo, flashed to a X850 XT PE. Omega 2.6.87 (CAT 5.12)DirectX 9.0cW XP Home with SP2E171FPb Flat panel monitor 17"370Gb HD (120 GB Maxtor, 250GB Samsung) 7200rpm ATA Lacie 250Gb Extern HDMy work:http://library.avsim.net/search.php?CatID=...&Go=Change+View

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