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Will the Marianas Map be shaped such that it fits on a sphere?


Northstar98

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Hi Everyone,

 

Does anybody know whether or not the Marianas map will transition away from the flat maps, and instead be shaped as a surface element of a sphere?

 

Like this (on the right):

 

a-System-of-coordinates-and-b-differenti

 

This map can be made quite expansive (and it looks like its planned to be about as expansive as the current Caucasus map), whereby having a flat map becomes less of an accurate approximation; it also means that RADARs won't have to employ a workaround to imitate LOS limitations on a spherical Earth - which also has the added benefits of having visual and RADAR LOS coincide with each other (as they should).

 

Also, if the end goal is to have the world in DCS World (even if it is a long way out) wouldn't it make more sense to have it fit into a sphere? How I imagine the world would work in DCS is you'd probably have generic terrain and airfields, and then have our current theatres replace certain areas - in exact same fashion to many flight simulators.  


Edited by Northstar98
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  • Northstar98 changed the title to Will the Marianas Map be a Spherical Cap?
  • 3 weeks later...
  • 3 weeks later...
On 2/18/2021 at 10:54 PM, 3WA said:

Interesting.  I wonder what it would take to "bend" it to spherical?  If possible.

 

I imagine everything in DCS is using a cartesian coordinate system (that's the x, y, z thing), but even so the maths for transferring one to the other isn't particularly difficult - it's fairly basic trigonometry.

 

In terms of bending flat maps into spherical ones, I'm currently working on a basic python script that works in 1 dimension (to do it in others, you just do the same thing for each axis) - I'm so far just working out the geometry, but I think I've gotten something.

 

Overall however, I think transitioning to a spherical coordinate system, and spherical maps would be a step in the right direction, it's certainly more accurate - especially for larger maps.


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On 3/6/2021 at 8:54 PM, Northstar98 said:

I imagine everything in DCS is using a cartesian coordinate system (that's the x, y, z thing), but even so the maths for transferring one to the other isn't particularly difficult - it's fairly basic trigonometry.

It's not difficult to understand, but it's actually pretty difficult to compute, for such a basic thing. In general, trigonometric functions are slow compared to arithmetics, and in performance-critical applications one needs to be careful with them. The coordinate system in particular is used everywhere, possibly meaning a lot of trigonometry going on, and a corresponding performance hit.

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1 hour ago, Dragon1-1 said:

It's not difficult to understand, but it's actually pretty difficult to compute, for such a basic thing. In general, trigonometric functions are slow compared to arithmetics, and in performance-critical applications one needs to be careful with them. The coordinate system in particular is used everywhere, possibly meaning a lot of trigonometry going on, and a corresponding performance hit.

 

Meh, there are plenty of applications (including flight simulators) using a spherical or cylindrical coordinate system, I'm not convinced it'll be a massive hit in comparison. Nor am I convinced you'd have to change everything to fit.

 

The main thing that's changing in terms of how DCS works, is a single vector for force (gravity), everything else basically stays the same. And even if it is more involved than that, don't forget that over current map sizes we're working with small angles (1° equates to an arc length of about ~110km so we're probably looking at about 10° maximum). I mean you could even use a look-up table here - it would be quite large no doubt about it, especially for larger maps, but it means you can keep the calculations purely arithmetic.

 

Only other thing I can think of is OTH ground-wave propagation for NDBs - not sure how DCS handles that. Things like RADARs can keep their current scan zones, but account for LOS (which they should already do - though the RADAR simulation is something else completely). Same thing for radios.

 

For bending maps to fit on spheres, you only have to do the operation once, and the Marianas should be very easy (very small usable land area, and each island by itself occupies incredibly small angles) - it would be the perfect map to try and trial this out.


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  • Northstar98 changed the title to Will the Marianas Map be shaped such that it fits on a sphere?
  • 3 weeks later...
6 hours ago, dorianR666 said:

it would break compatibility with all mission scripts, and likely with modules too.

 

im fairly sure we will never see spherical maps in dcs.

 

Well I doubt that, especially all mission scripts. Converting from cartesian to spherical polar is not hard. The only real difference in the physics between how it works now and how it'll work with a spherical map is the direction of gravity. Once you've got that, everything else can be converted.

 

And if it's too taxing from doing all the trigonometry, then you could do what I suggested above.

 

RADARs and radios work exactly as they do now - RADARs keep their scan zones and account for LOS, nothing changes. And I'm pretty sure DCS doesn't account for atmospheric phenomena with radios and RADAR (could be wrong though) and the only OTH capable radio system we have right now AFAIK are NDBs/ARKs which use groundwave propagation and does take into account night effect.

 

And I hate to think what the South Atlantic map will look like if it's flat, because based on the screenshots and how it works right now, the whole of Argentina is going to be off-axis - a problem with having flat maps that are very large.


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On 1/17/2021 at 10:05 AM, Northstar98 said:

Hi Everyone,

 

Does anybody know whether or not the Marianas map will transition away from the flat maps, and instead be shaped as a surface element of a sphere?

 

Like this (on the right):

 

a-System-of-coordinates-and-b-differenti

 

This map can be made quite expansive (and it looks like its planned to be about as expansive as the current Caucasus map), whereby having a flat map becomes less of an accurate approximation; it also means that RADARs won't have to employ a workaround to imitate LOS limitations on a spherical Earth - which also has the added benefits of having visual and RADAR LOS coincide with each other (as they should).

 

Also, if the end goal is to have the world in DCS World (even if it is a long way out) wouldn't it make more sense to have it fit into a sphere? How I imagine the world would work in DCS is you'd probably have generic terrain and airfields, and then have our current theatres replace certain areas - in exact same fashion to many flight simulators.  

 

 

Personally, and I get that the source code is complex and things take time and what not but over the years waiting for maps and constant request's, I would rather a 3rd Party create a Global Map and fill in the graphical landscape details.

 

Then you can select anywhere in the world to fly in and so on

 

 


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On 4/3/2021 at 12:17 PM, WRAITH said:

Personally, and I get that the source code is complex and things take time and what not but over the years waiting for maps and constant request's, I would rather a 3rd Party create a Global Map and fill in the graphical landscape details.

 

Then you can select anywhere in the world to fly in and so on

 

I mean a world map is obviously the overall goal, but it's more of a dream than something realistic in the near future.

 

As far as a full 3D spherical world goes I think the realistic thing to hope for is a more basic elevation mesh (to the level of the current Caucasus map at most) and satellite textures, with airfields that maybe have an accurate layout, but using generic assets. Then use autogen for anything else. Obviously something like Outerra would be a god send, but I don't think that's happening. 

 

Then what our current theatres would do is effectively overwrite the areas they cover, for people who own them - exactly like every other flight sim with a full spherical Earth. So you might initially have a more crude and low detailed Syria for instance, but if you own the Syria map, then that area will be replaced by the Syria map, again, in exactly the same fashion as basically every other flight simulator that has a world map.

 

However, for that to work, we first need our maps to conform to the shape of a sphere; obviously so they fit on one, but also because it's more accurate - which is especially important on larger maps (the Marianas in theory could be made really massive, without adding too much in the way of effort - something like 2000x1000km).


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  • ED Team

Hi all, please keep the discussion away from other sims.

 

thank you

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  • 3 weeks later...

Generally I would see such an engine change as something that wouldnt be un-announced. in my experience, if you are going to get something, you know in advance its coming. Something as fundamentally big as this anyway. If Marianas was suddenly curved, we could not expect the engine to support the 2D maps at the same time, its fundamentally incompatible.

As for missions, I dont think it would have any impact at all. The coordinate system would move with the game coordinate. theres an x,y,z of the 2D plain and coordinates are kindda fudged into it but they still absolutely return the long lat location.

Quite convinced you will know when its coming and that is not soon. As with all things in DCS, they tell you what you are going to get, like EDGE 1.2>2.5>2.7

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2 minutes ago, Pikey said:

Generally I would see such an engine change as something that wouldnt be un-announced. in my experience, if you are going to get something, you know in advance its coming. Something as fundamentally big as this anyway. If Marianas was suddenly curved, we could not expect the engine to support the 2D maps at the same time, its fundamentally incompatible.

 

In all honesty I have to agree, my only hope though is that it was stated (watch this space, I'll try and dig it up) that the Marianas will use some new terrain technology, but I don't think there was any detail on what the new technology would bring.

 

As for other flat maps, I wonder if it's possible to make the 2 systems independent, such that it uses the cartesian system on the current maps, and a spherical polar system (which is a transformed cartesian), on any future spherical surface maps if any.

 

2 minutes ago, Pikey said:

As for missions, I dont think it would have any impact at all. The coordinate system would move with the game coordinate. theres an x,y,z of the 2D plain and coordinates are kindda fudged into it but they still absolutely return the long lat location.

 

This is what I thought, even so, on the physics side, it changes one vector (gravity) and that's basically it, everything else either uses that vector or works the same way.

 

In any case it's not too much work in translating your x, y, z into spherical polar coordinates that work on a sphere, providing the terrain undergoes the same transformation.

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I think the most interesting conversation has to be as to what the catalyst is, for change to the world model, since it would invalidate the current terrains somewhat. I'm fearful of the death of maps like Syria with their detail level and replaced with detail that is terrible like another sim that uses the globe. It's not just the tech, but the business model and design. I wouldn't tolerate poor quality maps after what we have seen. The next iteration would mostly like beat that other sim, it would have to...

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2 hours ago, Pikey said:

I think the most interesting conversation has to be as to what the catalyst is, for change to the world model, since it would invalidate the current terrains somewhat.

 

I'm probably dreaming somewhat, but what I hoped would happen is there would be an algorithm to transform the current maps such that they would fit on a sphere. But it sounds like a hell of a lot of work.

 

2 hours ago, Pikey said:

I'm fearful of the death of maps like Syria with their detail level and replaced with detail that is terrible like another sim that uses the globe. It's not just the tech, but the business model and design. I wouldn't tolerate poor quality maps after what we have seen. The next iteration would mostly like beat that other sim, it would have to...

 

How I thought it would work is that we'd have a basic spherical map, and then our current theatres would replace the basic areas. I strongly doubt we would be able to see something like that other recent sim (for which our terrain would have to be detailed enough to support ground vehicles) even on storage space alone.

Modules I own: F-14A/B, Mi-24P, AV-8B N/A, AJS 37, F-5E-3, MiG-21bis, F-16CM, F/A-18C, Supercarrier, Mi-8MTV2, UH-1H, Mirage 2000C, FC3, MiG-15bis, Ka-50, A-10C (+ A-10C II), P-47D, P-51D, C-101, Yak-52, WWII Assets, CA, NS430, Hawk.

Terrains I own: South Atlantic, Syria, The Channel, SoH/PG, Marianas.

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A coordinate conversion from Cartesian to spherical would allow remorphing of the maps, but there's more to it. 

  • The equations of motion of all the moving objects (aircraft, missiles, ships, ground vehicles, projectiles) would have to be updated to include terms for Earth curvature (non-Cartesian) and Earth rotation (non-inertial), namely spherical coordinates with terms for spherical gravity, centrifugal acceleration, and Coriolis acceleration.  (See page 7 of this paper)*
  • Any aircraft or missiles with Inertial Navigation Systems would need to have their software updated to include the above Earth curvature and rotation effects. 
  • There may also be weapon targeting systems, such as electronic gun sights, that would need updates for Earth curvature and rotation as well.
  • While on a flat Earth all sunlight strikes the ground at the same angle, on a spherical surface the sunlight direction for shadows and reflections needs to be calculated as a function of latitude and longitude.  Maybe this could be ignored or simplified over the relatively small maps we have.
  • All line of sight calculations between any two objects on a spherical Earth need to calculate whether the LOS intersects the ground.  To be really good about it they should also add in atmospheric refraction, since in real life it allows you to see far beyond the true horizon.  Refraction depends on the wavelength of the radiation (visual light, infrared, radar, etc) and atmospheric conditions such as density and humidity.

* Alternatively, the equations of motion could remain Cartesian and inertial, but a whole bunch of additional conversion equations would be required to convert the Cartesian motion variables (position, velocity, attitude) into useful quantities relative to Earth and Earth's atmosphere.

 

This is not hard or groundbreaking, it's all very standard stuff that's present in a lot of high fidelity simulation software.  But it takes a ton of work along with checking and rechecking to get it all correct. 

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8 hours ago, Machalot said:

A coordinate conversion from Cartesian to spherical would allow remorphing of the maps, but there's more to it. 

  • The equations of motion of all the moving objects (aircraft, missiles, ships, ground vehicles, projectiles) would have to be updated to include terms for Earth curvature (non-Cartesian) and Earth rotation (non-inertial), namely spherical coordinates with terms for spherical gravity, centrifugal acceleration, and Coriolis acceleration.  (See page 7 of this paper)*

 

This depends on how DCS handles physics. All forces remain the same in a spherical coordinate system, the only one that really changes is the direction of weight (which would be radial instead of uniform (parallel)).

 

That direction should then affect things like the barometric equation (presumably we use that in DCS), but again, it's only accounting for the direction of g.

 

But the level of work depends on how the physics system already works in DCS.

 

For centrifugal acceleration, on a rotating body, well that's essentially just a subtraction to the magnitude of g (of course the amount of subtraction varies for different longitudes). The coriolis effect would be something new if we don't already do it (which I don't think we do). 

 

8 hours ago, Machalot said:
  • Any aircraft or missiles with Inertial Navigation Systems would need to have their software updated to include the above Earth curvature and rotation effects.

 

Probably Earth rotation effects more than anything (which they should have already). But again, unsure what DCS is using for its physics, but it's mostly just changing the direction of g so it acts radially instead of uniformly.

 

8 hours ago, Machalot said:
  • While on a flat Earth all sunlight strikes the ground at the same angle, on a spherical surface the sunlight direction for shadows and reflections needs to be calculated as a function of latitude and longitude. Maybe this could be ignored or simplified over the relatively small maps we have.

 

This shouldn't be too difficult to do, all we need is angle to the sun, and like you said, over small areas the difference isn't really all that significant or noticeable, so I'm not sure how necessary it is.

 

8 hours ago, Machalot said:
  • All line of sight calculations between any two objects on a spherical Earth need to calculate whether the LOS intersects the ground.

 

Personally, they should be doing this already, though I'm not sure how RADAR horizons work in DCS.

 

8 hours ago, Machalot said:

 To be really good about it they should also add in atmospheric refraction, since in real life it allows you to see far beyond the true horizon.  Refraction depends on the wavelength of the radiation (visual light, infrared, radar, etc) and atmospheric conditions such as density and humidity.

 

This would probably require a major overhaul to the weather system, and we'd probably also need to drastically overhaul the engine with ray-tracing to get it to work, and I'm not sure how feasible that is.

 

8 hours ago, Machalot said:

* Alternatively, the equations of motion could remain Cartesian and inertial, but a whole bunch of additional conversion equations would be required to convert the Cartesian motion variables (position, velocity, attitude) into useful quantities relative to Earth and Earth's atmosphere.

 

This is not hard or groundbreaking, it's all very standard stuff that's present in a lot of high fidelity simulation software.  But it takes a ton of work along with checking and rechecking to get it all correct. 

 

Agreed.

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7 hours ago, Northstar98 said:

All forces remain the same in a spherical coordinate system, the only one that really changes is the direction of weight (which would be radial instead of uniform (parallel)).

All real forces except gravity are physically the same magnitude but need to be converted to spherical coordinates.

7 hours ago, Northstar98 said:

That direction should then affect things like the barometric equation (presumably we use that in DCS), but again, it's only accounting for the direction of g.

I think it's more likely that DCS uses an atmosphere lookup table. The exponential model is not very accurate over large changes in altitude, and a table can be highly customized for variable weather conditions. Plus is is more computationally efficient to avoid exponentials.

 

7 hours ago, Northstar98 said:

For centrifugal acceleration, on a rotating body, well that's essentially just a subtraction to the magnitude of g (of course the amount of subtraction varies for different longitudes).

Centrifugal acceleration is "omega cross omega cross R", unrelated to gravity (omega is Earth rotation rate and R is aircraft position). Maybe you're thinking of a circular orbit where they happen to be equal? 

 

7 hours ago, Northstar98 said:

Probably Earth rotation effects more than anything (which they should have already). But again, unsure what DCS is using for its physics

If DCS uses a flat Earth it's unlikely they are modeling Earth rotation. 

 

Thanks for humoring me while I nerd out a little bit. This simulation modeling stuff is my favorite part of my day job. 

 

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On 4/25/2021 at 5:02 PM, Machalot said:

All real forces except gravity are physically the same magnitude but need to be converted to spherical coordinates.

 

I see, I was thinking that forces applies to objects would just go by the objects orientation, but then I realised that that only really holds true for thrust and maybe lift.

 

But even so the motion of any object would have to be converted to use a spherical coordinate system. 

 

I imagine I'm probably wrong (I only have rudimentary programming knowledge, barely beyond beginner) you're clearly more versed in this than I am. 

 

Quote

I think it's more likely that DCS uses an atmosphere lookup table. The exponential model is not very accurate over large changes in altitude, and a table can be highly customized for variable weather conditions. Plus is is more computationally efficient to avoid exponentials.

 

Centrifugal acceleration is "omega cross omega cross R", unrelated to gravity (omega is Earth rotation rate and R is aircraft position). Maybe you're thinking of a circular orbit where they happen to be equal?

 

Yeah, that was a complete brain fart on my part 😅

 

What I should've said is that over the equator centrifugal acceleration essentially just opposes g, which would just manifest as a reduction in the apparent weight. But as you change the latitude (not longitude as I said), it acts in a different direction. A component of it would oppose g (unless you're in line with the axis of rotation), but there's a component unaccounted for, which would need to be factored in. The saving grace though is that as the 2 vectors diverge in direction as we get closer to the poles, the magnitude of centrifugal acceleration also decreases (|a| =  ω2r where ω is the angular velocity and r is the distance to the axis of rotation).

 

But yes, it's still something we'd have to account for, though it shouldn't be too much hassle.

 

Quote

If DCS uses a flat Earth it's unlikely they are modeling Earth rotation.

 

I suppose you're probably right, yet another inaccuracy from having a flat Earth model.

 

Quote

Thanks for humoring me while I nerd out a little bit. This simulation modeling stuff is my favorite part of my day job.

 

Not a problem! I appreciate your input, and it is pretty interesting stuff, figuring out how this will all work.


Edited by Northstar98
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Modules I own: F-14A/B, Mi-24P, AV-8B N/A, AJS 37, F-5E-3, MiG-21bis, F-16CM, F/A-18C, Supercarrier, Mi-8MTV2, UH-1H, Mirage 2000C, FC3, MiG-15bis, Ka-50, A-10C (+ A-10C II), P-47D, P-51D, C-101, Yak-52, WWII Assets, CA, NS430, Hawk.

Terrains I own: South Atlantic, Syria, The Channel, SoH/PG, Marianas.

System:

GIGABYTE B650 AORUS ELITE AX, AMD Ryzen 5 7600, Corsair Vengeance DDR5-5200 32 GB, Western Digital Black SN850X 1 TB (DCS dedicated) & 2 TB NVMe SSDs, Corsair RM850X 850 W, NZXT H7 Flow, MSI G274CV.

Peripherals: VKB Gunfighter Mk.II w. MCG Pro, MFG Crosswind V3 Graphite, Logitech Extreme 3D Pro.

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  • 2 months later...

Just an update - unfortunately the Marianas map is flat just like every other map.

 

Oh well, it still stands to be the most viable map to be shaped such that it fits on a sphere.


Edited by Northstar98
  • Like 1

Modules I own: F-14A/B, Mi-24P, AV-8B N/A, AJS 37, F-5E-3, MiG-21bis, F-16CM, F/A-18C, Supercarrier, Mi-8MTV2, UH-1H, Mirage 2000C, FC3, MiG-15bis, Ka-50, A-10C (+ A-10C II), P-47D, P-51D, C-101, Yak-52, WWII Assets, CA, NS430, Hawk.

Terrains I own: South Atlantic, Syria, The Channel, SoH/PG, Marianas.

System:

GIGABYTE B650 AORUS ELITE AX, AMD Ryzen 5 7600, Corsair Vengeance DDR5-5200 32 GB, Western Digital Black SN850X 1 TB (DCS dedicated) & 2 TB NVMe SSDs, Corsair RM850X 850 W, NZXT H7 Flow, MSI G274CV.

Peripherals: VKB Gunfighter Mk.II w. MCG Pro, MFG Crosswind V3 Graphite, Logitech Extreme 3D Pro.

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9 hours ago, Northstar98 said:

Just an update - unfortunately the Marianas map is flat just like every other map.

 

Oh well, it still stands to be the most viable map to be shaped such that it fits on a sphere.

 

As we discussed, there's no use making a curved map with the flat Earth dynamics model DCS presumably has now.

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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