Physics (mechanics)

The most appropriate place for Questions, Queries, and Quandaries regarding the nature of the Vega Strike universe and its past, present, or future history. Home to the occasional unfortunate RetCon.
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TBeholder
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Physics (mechanics)

Post by TBeholder »

It's nice that there's OpenSource space simulator. I'll download it soon.
But i have one question about the very nature of The Vega Strike Universe (well... anyway, i can't imagine in what other forum i can put this :wink:).
:?: What physics is used ? :?:
I.e. generally 2 physics models are used in space simulators:
1) "liquid vacuum" physics (like in "Wing Commander") - speed is absolute, limited and ship with no active engines hangs and
2) "real" physics (like in "Elite 3: First Encounters", FFE) - ship moves according to the laws of gravitation, of conservation of momentum, etc - e.g. ship can be placed on elliptical orbit and constant acceleration allows to move faster and faster relative to any chosen object, not to constant movement at some "maximal" speed.
Which one is used ?
From wiki-manual i can't understand - whether velocity relative to another object is calculated from absolute speeds in "liquid" space or intricate drives control allows "absolute" positioning in normal space ?..

I suppose in OpenSource engine physics model can be changed with some efforts (as anything else), but what physics is used in VegaStrike itself ?

Of course, without time acceleration modes observation of an orbit is harder than in FFE, but can pilot see orbiting ships and other objects (if proper trajectories are arranged) at all ? Is there such thing as a "maximal speed" (other than light speed :wink: ) obtainable with constant acceleration (without use of SPEC-drives or jumps) ?
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Post by Halleck »

I think that our physics model is closer to "real" (newtonian) physics. Gravity is not modelled AFAIK, but orbits are simulated. You can see this if you use the time compression debugging feature... f9 to step up time (you'll have to press it a lot) and f10 to reset. Be warned it's buggy and may cause unpredictable effects.

The one thing is, our flight model feels a bit more like a wing commander type game because the onboard flight computer is made to "compensate". For instance, if you cut throttle, your ship will decelerate to a standstill relative to your frame of reference object, because your ship has automatically fired retro-rockets. (This function can be disabled with the shelton slide key.) Another example is the "speed limit", or speed cap. If you press max throttle, your ship will accellerate until it reaches a certain velocity, and then stop accellerating. This is to keep maneuvering simple. However, you can press [Y] to toggle the speed cap, allowing your top speed to be essentially limitless (although there is a mathematical limit in the simulation, but that's more of a technical limitation since you're rarely going to be travelling at such insane velocities.)

Velocity is measured on a relative scale. You pick a frame of reference by targeting it and pressing the [home] key. I think the sun is the default frame of reference. Then, your velocity is measured relative to that object... so if I set a space station as my frame of reference, get close to it, and cut throttle, I will remain stationary relative to the station even if we are still orbiting a planet.

You can test this out in high-speed time compression... get things moving fast enough so you can observe orbits, and then use [home] to switch your frame of reference. You will see that your ship will remain stationary relative to the object of your choice, because your flight computer is automatically firing manuvering jets to match velocity.
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Post by AlbertSpeer »

Why do the main engines on ships continue firing when the ship is maintaining a constant velocity? I understand that they'd need to produce a very small force to counteract drag, since space isn't a perfect vacuum, but the engine graphics ought not to be at full once constant velocity is reached.
Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the direction of thine foe, who, being naughty in my sight, shall snuff it."
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GC/CS/E/IT/M/S d+ s+:+ a--->? C+++ UB+++/L+/X+ P+ L+>+++++ E--- W++>+++ N- !o K w--- ?O M++>$ ?V PS+++ PE-- Y+ PGP- t 5++ R tv-- b+++>++++$ DI++++>$ D++ G++>+++++ e->+++++ h! r->r+++ y-
------END GEEK CODE BLOCK------
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Post by klauss »

AlbertSpeer wrote:Why do the main engines on ships continue firing when the ship is maintaining a constant velocity?
They don't. Not in SVN. What are you using? 0.4.3?
AlbertSpeer wrote:I understand that they'd need to produce a very small force to counteract drag, since space isn't a perfect vacuum
Maaaaybe solar winds. Maybe. But interstellar medium? It doesn't amount considerable drag... no...
AlbertSpeer wrote:but the engine graphics ought not to be at full once constant velocity is reached.
REP: They don't.
They do however "flash", I've been meaning to correct that, but I haven't settled on what form the correction should take. Should they stay on at minimum output (best looks, IMO), or should they be completely off (and steadily off - most realistic, IMO).
I really dunno.
When I get tired of working on what I'm working, which is a big boring, I'll play with it a bit.
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Post by AlbertSpeer »

klauss wrote:
AlbertSpeer wrote:Why do the main engines on ships continue firing when the ship is maintaining a constant velocity?
They don't. Not in SVN. What are you using? 0.4.3?
Yeah, I'm using 0.4.3. I downloaded the SVN version, but it adamantly refuses to load my data files.
Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the direction of thine foe, who, being naughty in my sight, shall snuff it."
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GC/CS/E/IT/M/S d+ s+:+ a--->? C+++ UB+++/L+/X+ P+ L+>+++++ E--- W++>+++ N- !o K w--- ?O M++>$ ?V PS+++ PE-- Y+ PGP- t 5++ R tv-- b+++>++++$ DI++++>$ D++ G++>+++++ e->+++++ h! r->r+++ y-
------END GEEK CODE BLOCK------
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Post by klauss »

You'd need SVN data too.
You have to check out the entire data4.x, music (if you want music) and if you're in linux, vegastrike (so you can build it).
You place your executable (it's already there if you're using windows) in data4.x/bin, and play straight from there (it's not "the" way to play, but I found it very easy and handy).

The wiki has instructions, IIRC.
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AlbertSpeer
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Post by AlbertSpeer »

klauss wrote:You'd need SVN data too.
You have to check out the entire data4.x, music (if you want music) and if you're in linux, vegastrike (so you can build it).
You place your executable (it's already there if you're using windows) in data4.x/bin, and play straight from there (it's not "the" way to play, but I found it very easy and handy).

The wiki has instructions, IIRC.
Turns out I had the executables in data4.x. I've downloaded everything, and even after I added symlinks in data4.x/bin, it still does the same thing it did before: print out a lot of error messages.
First, there's a few hundred instances of this:

Code: Select all

Launch nexting areus
 File is a directory !  File is a directory ! Unit file areus not found
Assertion failed unit_generic.cpp:711 Unit areus not found
Warning: Cannot locate areus
aeralaunched galena:areus0-8(813623962.10738349, -744341188.4339999, -545762878.70759261)
Then there's a lot of this:

Code: Select all

Launch nexting hyena.blank
Unit file hyena.blank not found
Assertion failed unit_generic.cpp:711 Unit hyena.blank not found
Warning: Cannot locate hyena.blank
pirateslaunched Bahama:hyena.blank0-8upgrading LOAD_FAILED laser01 0 0 true
upgrading LOAD_FAILED laser01 1 0 true
upgrading LOAD_FAILED engine00 0 0 false
upgrading LOAD_FAILED reactor02 0 0 false
Upgrading Engine engine00 percent 0.000000
upgrading LOAD_FAILED dualshield01 0 0 false
Upgrading Shield2 level 0... percent=0.0
upgrading LOAD_FAILED quadshield01 0 0 false
Upgrading Shield4 level 0... percent=0.0
UpgradeError finding upgrades/Sensors/Intermediate using upgrades/Sensors instead
UpgradeError: terrible error lasers instead
upgrading LOAD_FAILED  0 0 false
upgrading LOAD_FAILED mult_overdrive01 0 0 false
upgrading LOAD_FAILED jump_drive 1 1 true
UpgradeError: terrible error lasers instead
error.. cargo not found
error.. cargo not found
UpgradeError finding upgrades/Ammunition/3pack using upgrades/Ammunition instead
UpgradeError: terrible error lasers instead
error.. cargo not found
the last thing is many, many of these:

Code: Select all

nonzeroing
finding quest
quest_drone
resetting sigdist=8000.000000 detdist=40000.000000
LOAD_FAILED:llama.civvie Magnuson going to Jump_To_Stirling:jump
LOAD_FAILED:sartre.civvie Godzilla going to Jump_To_Callisto:jump
LOAD_FAILED:llama.civvie Godzilla going to Jump_To_Stirling:jump
LOAD_FAILED:ox Maxwell going to Jump_To_Cardell:jump
LOAD_FAILED:llama.civvie Badb going to Jump_To_Dakota:jump
LOAD_FAILED:llama.civvie Jarvin going to Jump_To_Stirling:jump
LOAD_FAILED:llama.civvie Clemens going to Jump_To_Cardell:jump
LOAD_FAILED:quicksilver.civvie Johnstown going to Jump_To_Maat:jump
Any idea what I've done wrong?
btw:
- When I try external views of my ship, which the nav comp tells me is a derivative, nothing shows up.
- The nav comp tells me that the load of my ship failed
- Even though things are talking to me, I can't target them (do they exist?)

Any help would be appreciated. This is all on Mac OS X 10.4.8.
Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the direction of thine foe, who, being naughty in my sight, shall snuff it."
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GC/CS/E/IT/M/S d+ s+:+ a--->? C+++ UB+++/L+/X+ P+ L+>+++++ E--- W++>+++ N- !o K w--- ?O M++>$ ?V PS+++ PE-- Y+ PGP- t 5++ R tv-- b+++>++++$ DI++++>$ D++ G++>+++++ e->+++++ h! r->r+++ y-
------END GEEK CODE BLOCK------
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Post by klauss »

Those messages are "normal" in the current state of things.
Some ships are actually missing on the units.csv, ships that are referenced on python code.
(@dan, you probably want to take a look at that)

But the derivative works - your problem is probably a "savegame compatibility issue". Try if starting a new game fixes most of your issues. If it does, I'd recommend hacking a newly created game to add the credits necessary to re-purchase your stuff - that'd be the safest & straightforwardest way of approaching the problem, IMO.
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AlbertSpeer
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Post by AlbertSpeer »

stupid question... but how do I start a new game? I start in space, and I can't fly anywhere, since whatever the engine thinks I'm flying has a max speed of 1 and no SPEC.
Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the direction of thine foe, who, being naughty in my sight, shall snuff it."
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GC/CS/E/IT/M/S d+ s+:+ a--->? C+++ UB+++/L+/X+ P+ L+>+++++ E--- W++>+++ N- !o K w--- ?O M++>$ ?V PS+++ PE-- Y+ PGP- t 5++ R tv-- b+++>++++$ DI++++>$ D++ G++>+++++ e->+++++ h! r->r+++ y-
------END GEEK CODE BLOCK------
klauss
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Post by klauss »

You must have ejected.
You can hit Shift+1 and suicide yourself. You'll be given the option to load a saved game (supposedly with your ship).
If that fails (you somehow saved after you ejected), you could force VS to load a new game at startup by editing .vegastrike/save.4.x.txt - just replace what it says by New_Game.
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Post by daschapa »

Halleck wrote:I think that our physics model is closer to "real" (newtonian) physics.
My comment is quit off-topic, but I think it's good to know: "Newtonian" physics are not exactly real, since the Eintein's Theory of Relativity.
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Post by loki1950 »

only at relativitic velocity which we don't aceave :wink:

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