GT: Far Trader: Jump Masking

[Malenfant]

Originally posted by Jamus:
gonna have to ask why the size of a planet or star should matter if not for the gravity well said body would imprint on the fabric of space?

Beats the hell out of me

. The implication in the OTU and from what Marc's said is quite clearly though that it's only the size that matters, not the mass or gravity. It's entirely arbitrary and makes no sense at all from a physical or realistic point of view.

to me it is all about the affect of gravity on space.

Yes, I'd agree, and that's what people like me are arguing for by making it dependent on the local strength of the gravitational field rather than setting it at an arbitrary distance that depends on a fixed multiple of the diameter of the object.

 

[kaladorn]

RoS, you've addressed all sorts of reasons related to your perception of how important the whole Masking issue is to believability. Oddly, most of my players wouldn't bat an eyelid one way or the other. So I'd call it a very small corner of the game and therefore not that significant either way.

But having said that, we aren't aware of every property of matter nor of alternate spaces. I'm not saying it is likely that something in our 3-space will exhibit a matter-based (ie radius based) property that is not related to density on some alternate space (Jump Space), but really there isn't any basis that I can think of to say that it isn't possible.

And you've missed, IMO, the most important part of the game aspect - Masking has some interesting consequences for players in the game. Gravity based shadowing could work too, but I have run into systems where it would *really* bugger up commerce. You'd have to rewrite a few trade lanes as a consequence and while we're at it, why don't we talk about revamping all the UWPs to see populations distributed where it makes some sense for trade or for planetary habitability? I think you start tugging at one thread, many things unravel. But Masking, as an idea for a role-playing impediment, is fine. It serves that purpose admirably. It has shortcomings, but I suspect more for those who (as Larsen puts it) 'play with Traveller' than for those who 'play Traveller'. Heck, those in the latter camp don't even mind the mis-spelling of vaccuum.

To summarize:
1) There is lots of existing canon
2) There is no pressing reason to change it (you could argue there is a need to clarify it)
3) There is a role-playing function that it serves
4) There could be some property of matter that is not related to density that applies here. I'm not sure I have any idea what, but usually when people say what can and can't happen, in the long run, they're proven wrong or partially wrong. In this case, I'm willing to buy 'Jump Space' so I'm more than willing to buy 'Jump Masking'. The whole ecliptic issue is a red herring because it could easily be that all of those objects arrayed at varying Z values in our 3-space map to some sort of flat plane in J-space and thus the ecliptics are utterly irrelevant. We don't know... and thus... it all boils down to speculation... and I think it is fait accomplit.

Fill yer boots, evangelize for the change, but I think you should be prepared to be disappointed.

 

[hcobb]

I like tidal force jump masking, which gives similar results to the diameter limit modulo the density ratio.

 

[Malenfant]

Originally posted by kaladorn:
RoS, you've addressed all sorts of reasons related to your perception of how important the whole Masking issue is to believability. Oddly, most of my players wouldn't bat an eyelid one way or the other. So I'd call it a very small corner of the game and therefore not that significant either way.

Of course one could argue that anything that doesn't affect actual gameplay is irrelevant. But there are some people for which believability/consistency/realism/umambiguity in the background is also important.

I don't think either is more important than the other, though ideally I would like a realistic solution that does not hinder gameplay

.

 

[RainOfSteel]

Originally posted by kaladorn:
Oddly, most of my players wouldn't bat an eyelid one way or the other.

Excellent news! That means they won’t object to a Gravity Jump Limits & Shadowing system.

Originally posted by kaladorn:
And you've missed, IMO, the most important part of the game aspect - Masking has some interesting consequences for players in the game.

There are extra problems that I’m not yet aware of? Please, post back, I’m willing to extend the list.

Originally posted by kaladorn:
Gravity based shadowing could work too, but I have run into systems where it would *really* bugger up commerce. You'd have to rewrite a few trade lanes as a consequence

AFAIK, Masking encompasses Shadowing, and applies its own additional restrictions. Shadowing is must less restrictive than Masking. It would therefore seem to me that Trade routes would be opened up by going only with Shadowing, rather than the vastly more restrictive Masking.

Originally posted by kaladorn:
and while we're at it, why don't we talk about revamping all the UWPs to see populations distributed where it makes some sense for trade or for planetary habitability?

Yes! Yes! Yes! We’re definitely going down the same street on that one.

Originally posted by kaladorn:
I think you start tugging at one thread, many things unravel.

Masking is a thread, left out of the original weave by accident, that was added in later. We unravel nothing by it’s removal, but instead eliminate a tangled web caused by its presence.

Originally posted by kaladorn:
But Masking, as an idea for a role-playing impediment, is fine. It serves that purpose admirably.

What purpose?

Ruining the starship economic systems of CT or T20 (if applied to those settings)?

Needless complication of interstellar travel that is already sufficiently odd in comparison to most other forms of SF FTL propulsion?

Originally posted by kaladorn:
2) There is no pressing reason to change it (you could argue there is a need to clarify it)

I’d say my previous posts show a major need to change it.

Originally posted by kaladorn:
3) There is a role-playing function that it serves

I haven’t seen it. (Please post back with an explanation.)

Originally posted by kaladorn:

4) There could be some property of matter that is not related to density that applies here. I'm not sure I have any idea what, but usually when people say what can and can't happen, in the long run, they're proven wrong or partially wrong. In this case, I'm willing to buy 'Jump Space' so I'm more than willing to buy 'Jump Masking'. The whole ecliptic issue is a red herring because it could easily be that all of those objects arrayed at varying Z values in our 3-space map to some sort of flat plane in J-space and thus the ecliptics are utterly irrelevant. We don't know... and thus... it all boils down to speculation... and I think it is fait accomplit.

And that’s exactly the type of discussion that shouldn’t appear in an explanation of SF game technologies. “There could be”, “I’m not sure”, “have any idea”.

I couldn’t have more trouble with the above statement than if I heard it while watching Star-Trek.

Originally posted by kaladorn:
Fill yer boots, evangelize for the change, but I think you should be prepared to be disappointed.

And this means I should quit without even trying? Sorry, it ain’t gonna happen.

 

[TheEngineer]

Hi !

IMHO regardless what kind of masking/shadowing system you might use, the TU ought to be adapted to this situation.
Its like if the ocean sealevel decreases some 100 meters, that might change the topology of civilisation (location of cities, habours etc), but there is still trade following the same rules as it does now.
What might be wrong is just to change one aspect of the TU without changing related aspects. Thats the thing happend in the whole discussion since 1985. They talked about just one aspect of the universe in a separated way, mostly ignoring the overall consequences.
So any change of the distribution of jump friendly space should directly modify the location finding for a mainworld or at least a starport and maybe, like in MTU adds some farports.

In a consequence the regular procedure to do trade and commerce might work, regardless which model You might choose.
IMTU I work with the tidal model, masking/shadowing, lately with real 3D space mapped to jump space and with stored values for planetary system ecliptics and mainworld positions.
It added some "feeling of realism" but all in all and to my own surprise (and some frustration, because all of the work) the consequences were nearly neglegtable. I even didnt need to use the curved-jump plot solution, which generally takes out the masking problem.

Sometimes we are very keen on creating problems in order to have something to be solved

.
As long its fun....

Regards,

Mert

 

[Jamus]

It was my belief that a ship would accelerate out of system to well beyond the local gravity wells to a marked and charted jump point, hit the j-drive and slip into jump space. one week later said ship re-enters real space well beyond its target systems gravity well and begins to decelerate to the target world. on your average trader I have always ran it that each leg of the journey would take about a week or three weeks in total.

I have been mulling over the instant jump idea also, thus 1 week to reach the jump point, instant jump to target jump point, one week to reach target world for two week total jump time. this idea does away with the idea of j-space and speculates that j-drives work by folding space between two points ala Dune's traveling without moving approach. yet another idea i have thought about was that the jump would take a week also but would seem instant to the persons on the ship.

anyways that should be enough rambling from me for a minute or two.

 

[TheEngineer]

Hm, interesting too.
But think of the consequences.
What I would consider first is e.g. the speed of communication change, no more one week delay per jump...

Guess that would change quite a bit.

 

[kaladorn]

I agree with Mert. With one caveat: Is there a hidden assumption that the current layout of Trade Lanes, etc. corresponds to existing trade rules of any flavour and was developed thus? If so, I'd bet it was a wrong assumption.

It would be nice to see a TU laid out with at least passing reference to economics and true habitability.

I'm not going to argue with Rain, not because I couldn't, but because I'm not going to win in the long run, and the argument is a loss. My players won't care what is done, because it will be up to me to figure it out. I'm happy with 100D as brutally simple and sufficient. Jump Masking is interesting, and intermittently I consider it, at other times not.

I agree with Mal that it matters for some folk, but I'm betting most of them are people who tinker with the universe, not run games in it (some few may do both).

So, fill yer boots, argue away. I think the one person you'd need to convince isn't going to be too worried about it.

 

[castlebravo]

I agree with Mel and others that the mass of local objects in space (and thereby the gravitational field) should be the explanation used to limit objects from jumping into and out of systems close to other objects such as planets/worlds. IMO, however, the limit provided by the 100D rule makes a great deal of sense and any gravitational rule should reflect approximately the same distance whenever possible.

First why did Marc decide to make any limit necessary in the first place? I think because the closer an object is able to ‘materialize’ from jump-space in the vicinity of a world or some other area of key terrain, the less use for ships, a navy, or naval weapons in the game. I think you can all see how this simple change could effect the overall setting and themes of Traveller… in effect no more ‘blue-water’ ships and adventure on the ‘high-seas’ of space. An attacker simply jumps drones at high speed into high orbit above a target and the battle is lightning fast as the bombs overwhelm the point-defenses and strike or are destroyed and the attack is a failure. No more pirates, etc.

Regardless of how you explain the need to keep shipping from leaving and entering the safety of port immediately, the 100D distance provided by Marc is about correct given the effective weapons ranges and subluminal speed of ships in Traveller.

 

[flykiller]

I suspect more for those who (as Larsen puts it) 'play with Traveller' than for those who 'play Traveller'. Heck, those in the latter camp don't even mind the mis-spelling of vaccuum.

(laugh) no, we don't. we don't have time.

 

[Malenfant]

Originally posted by Castlebravo15:
I agree with Mel and others that the mass of local objects in space (and thereby the gravitational field) should be the explanation used to limit objects from jumping into and out of systems close to other objects such as planets/worlds. IMO, however, the limit provided by the 100D rule makes a great deal of sense and any gravitational rule should reflect approximately the same distance whenever possible.

Right, but as I've been showing (repeatedly) here that's not possible. Gravitational field strength is different at 100 diameters from bodies with different mass - therefore 100D is an approximiation to nothing at all. If gravity is 0.001m/s2 around one object at 100D, it might be 0.1m/s2 around another, and 0.32m/s2 around another and so on. Even if you replace 100D with "always at one million km from the object" and not tie it to the object's diameter, the gravitational field at that distance is still different for different bodies because they have different masses.

The only way to make sense of this is to say that the jump limit is at a certain gravitational field strength (or at least something to do with gravity, like tidal stress), and either calculate that for bodies with different masses or have a look-up table for it. Anything else is simply nonsensical.

 

[RainOfSteel]

If only one person needs to be convinced of anything, and that person won't change their mind about anything, then there is no reason to run a playtest of T5.

 

[Jamus]

the good news is I can run this however I choose in MTU though i do try to follow the mechanics presented in OTU. MM didnt really explain why the 100 diameters so I basically fed the gravity well idea to my players, they bought it and thats been that ever since.

do agree with the poster that pointed out removing the limit would radically alter the game as far as system encounters go. makes alot of sense.

 

[castlebravo]

Originally posted by Malenfant:
Right, but as I've been showing (repeatedly) here that's not possible. Gravitational field strength is different at 100 diameters from bodies with different mass - therefore 100D is an approximiation to nothing at all. If gravity is 0.001m/s2 around one object at 100D, it might be 0.1m/s2 around another, and 0.32m/s2 around another and so on. Even if you replace 100D with "always at one million km from the object" and not tie it to the object's diameter, the gravitational field at that distance is still different for different bodies because they have different masses.

The only way to make sense of this is to say that the jump limit is at a certain gravitational field strength (or at least something to do with gravity, like tidal stress), and either calculate that for bodies with different masses or have a look-up table for it. Anything else is simply nonsensical.

Or you could approach the problem from a different direction and instead generalize the mass of objects in order to balance the gameplay. It isn't necessary for every planet and every star to have a unique mass. Malenfant did a good job of showing the three major categories already... planetoids, jovian-type gas giants, and stars. There are definite orders of magnitude there already. The most important point is that the reason behind the rule has a basis in scientific fact... not the accuracy between a 0.009 AU limit and a 0.001 AU limit.



EDIT: Corrected spelling of Malenfant's name. Sorry about that!

 

[Malenfant]

Who's Mel?

Again, problem is that masses aren't nicely divided like that. Terrestrial planets go from 0.1 to 10 earth masses, Gas giants from 10 earth mases to 13 Jupiter masses, Brown dwarfs from 13 jupiter masses to 70 Jupiter masses, stars from 0.07 solar masses to 15 and beyond.

You can't just do lip service to realism by saying "this limit is based on gravity" and then come up with numbers that ignore that. You can generalise to an extent, but you can't say that all planets have a limit at distance X, all stars have it at distance Y, and all planetoids have it at distance Z - Luna's jump limit is very different to Venus' jump limit. Neptune's is very different to Jupiter's. Sol's is very different to Proxima's and Antares'.

 

[castlebravo]

Originally posted by Malenfant:
You can't just do lip service to realism by saying "this limit is based on gravity" and then come up with numbers that ignore that.

Using approximations and algorithms is not lip-service, it is exactly what games do. Even simulations dumb down variables. After all, why are you ignoring the mass of the ship conducting the jump? Would not the mass of ship influence the gravitational force as well? Now we know that m (the mass of the ship) is usually taken to be a "test particle" so that m << M, because it isn't significant to the model.

Originally posted by Malenfant:
You can generalise to an extent, but you can't say that all planets have a limit at distance X, all stars have it at distance Y, and all planetoids have it at distance Z - Luna's jump limit is very different to Venus' jump limit. (*SNIP*)

By your chart, Luna's jump limit is 19,966 km. and Venus' jump limit is 178,579 km. At face value it is more than a 158K difference, but what is the relative effect in gameplay? Is that 158K significant to the overall intent, which is to force the availability of ship-to-ship encounters in 'deep' space? If anything, Luna's limit is to close. The fact that we could just pay lip service to the difference and ignore the 158K between Luna and Venus, doesn't effect the player's overall suspension of disbelief because we have stated a reasonably generic excuse for a limit on a fictional technology (jump engines)... a more reasonable excuse than 100 diameters.

 

[mike wightman]

It could be that considering the effective field strength of gravity is the wrong way to do it - at least in our universe

One of the latest theories is that gravity propogates though the extra dimensions predicted by string and M theory.

The 100D limit could be based on the gravitational effect from "the other side of the mirror".

 

[RainOfSteel]

I was going to go over some hair-splitting, but I've deleted it.

My original recommendations stand.

Whether they'll be acted upon, well, kaladorn is probably right.

 

[TheEngineer]

Is it really a problem to just use another table with a somehow realistic size-jump limit information ?