Spacecraft

[Atgxtg]

Just a idea, but I was thinking of doing a design system that sort of works outside of BRP, but which would give BRP stats.

When you build the ship, you'd pick a hull size, in tons, and then use the tonnage as points to buy systems. For example, you could decide to make a 100 ton ship, and a rocket engine might yield, say 75 tons of thrust per ton of engine. So if you bought a 2 ton rocket engine, you'd get 1500 tons of thrust. Since 150 tons of thrust divided by 100 tons of mass is 1.5, the ship would have an acceleration of 1.5Gs.

We could then use the SIZ table to get a SIZ for the ship, using the 100 tons of mass, a STR for the engines, using the 150 tons of thrust, an ACC for the ship (multiple the Gs by 10) and so on. Basically a lot of this stuff is easier to do with real world math than with BRP terms. And a couple of tables or a spreadsheet could convert real world numbers that I think we can all get out heads around into RPG speak.

Does this approach make sense?

[nclarke]

This sounds extremely interesting. Just enough abstraction to make it easy to work with, just enough crunch to satisfy the need for technical detail. Differing levels of technology can be easily dealt with by varying the power output/ton of the motive power unit. It would even work backwards for non/pre-space vehicles.

How would you deal with the computational needs for targeting and navigation? The networked terminals style of early Traveller or perhaps independent units in a distributed processing system. Slave worked for Blake's Seven to deal with both targeting and navigation/sensors as a single unit but that sort of thing is subject to failure/damage of a single unit that makes it not sensible for manned space travel (having worked for NASA in the past this always strikes a warning note in space games I play).

[Guest Vile Traveller]

I'm quite intrigued by the potential of Pirates of Legend for adaption to space. But I'm too busy now.

[soltakss]

Yes, it makes a lot of sense.

[Atgxtg]

THanks for the feedback. I'll put togeth some bare bones stuff to see how it looks.

This sounds extremely interesting. Just enough abstraction to make it easy to work with, just enough crunch to satisfy the need for technical detail.

Well, after working of vehicle design rules off and on for several RPGs over the last few years, I learned something about how things work, and have come to the realization that often the design rules for RPGs are more complicated that the real world math! Also, there are a lot of times where it is easier to play with real numbers. Like when dealing with cargo capacity, or determining if something will fit though the hatch.

I figure that each ton of size would translate to roughly 3 cubic meters of volume. So those who want them can do up deck plans, or at least get an idea of how big thier ship is.

Differing levels of technology can be easily dealt with by varying the power output/ton of the motive power unit. It would even work backwards for non/pre-space vehicles

Yeah. I've been toying around with the idea of a scale of Technology Levels. A culture capable of space travel would be TECH 1. Earth in the 1960s would be TECH 1. Non-sparefaring cultures would have a decimal rating, and more advanced culture would have a higher rating. And there is a little wiggle room for play, too. Somebody might use a less advanced design to save money. The thrust/ton of engines would by adjusted by the TL. The F-1 thruster from a Saturn V rocket has a thrust/weight ratio of around 94, which is close enough to 100 that so I can set a TECH 1 rocket engine to a 100:1 ratio. Some modern engines seem to be at 160:1, so if TECH ratings are linerar (and right now I don't know if that is good or not) then a modern engine would be TECH 1.6.

Te same idea would apply to other systems. So a TECH 10 culture (whatever that means, perhaps FTL travel?) would have more advanced systems. I also figure TECH will handle the real world problems with fuel. At TECH 1, a ship might need to be 90% fuel, while at higher TLS only a small percentage of the ship is fuel.

How would you deal with the computational needs for targeting and navigation? The networked terminals style of early Traveller or perhaps independent units in a distributed processing system. Slave worked for Blake's Seven to deal with both targeting and navigation/sensors as a single unit but that sort of thing is subject to failure/damage of a single unit that makes it not sensible for manned space travel (having worked for NASA in the past this always strikes a warning note in space games I play).

Fairly abstractly. I don't plan to get a degree in astrophysics just to write this, and I certainly don;t want GMs and players to get a degree just to design a ship or play in an RPG. What I'd probably do is scale the performance to TECH somehow. More advanced sensors would get a bonus, have better range, resolution, be able tot rack multiple targets, etc.

As far a targeting goes, I supposed I'd have to allow for either route. Designers could opt to buy a targeting system for each weapon, or some sort of master system that handles everything. Although without a hit location or critical hit table it might be a moot point in play.

One additional perk about this approach that I just realized is that it makes it easier for other to expand upon. Using tonnages and TECH rating mades things fairly modular. So somebody could come up with spot rules for engines/weapons/whatever for a specific setting.

[RosenMcStern]

Having just finished to put up the rules for spacecraft for BRP Mecha, I have one question to ask.

Are you sure that all this is necessary for all genres?

For instance, I completely eliminated STR for big ships and kept SIZ for HP determination only. I could have ditched it, too. I simply did not need to determine how fast big ships moved or accelerated in comparison to other big ships. This might be relevant for a space pirate game, of course, but this point is totally genre-dependent, and sci-fi is not one single genre.

[dragonewt]

For instance, I completely eliminated STR for big ships and kept SIZ for HP determination only.

What about structural durability of the space-frame (STR)?

[Atgxtg]

Having just finished to put up the rules for spacecraft for BRP Mecha, I have one question to ask.

Are you sure that all this is necessary for all genres?

I know it's not. That's one reason why I took this approach. For the most part we really don't need to know what the SIZ is for a laser cannon. We just need to know if we can fit it on our ship. I figure that with a lot of this, as far as use goes, GMs will only do the work that they need to do. Now the spreadhseet I'm working on to test this out will crunch the numbers, but there is no reason for GMs and players to track anything they don't need. FOr instance, the spreadhseet track the surface area of the vehicle for armoring purposes. So, while you will be able to tell how much surface area the ship has, if you don;t need it, you won't bother with that part.

For the most part, people can just plug in some values into the data section, and sheet will spit out BRP game stats for them.

I could set it up so that the player selects the performance he wants (SIZ, ACC, MOV, Handling,) and the program works out what engines are required and such.

For instance, I completely eliminated STR for big ships and kept SIZ for HP determination only. I could have ditched it, too. I simply did not need to determine how fast big ships moved or accelerated in comparison to other big ships. This might be relevant for a space pirate game, of course, but this point is totally genre-dependent, and sci-fi is not one single genre.

Yeah, but what happens if the PCs (in one big ship) are trying to outrun the bad guys (in another big ship)? Or if somebody uses a tractor beam? Now if these aren't possibilties in a GM's campaign, then he wouldn't need to track stuff like STR, ACC< Handling, or MOV. But...he'd still need to worry about things like armor and weapons.

[Atgxtg]

What about structural durability of the space-frame (STR)?

Sorry, I think both ROsen and I were reffering to STR in terms of the ability to apply a Force (i.e. thrust). For structural durability I've been using CONstruction, armor and/or hit points. A ship will need a certain amount of CON to keep from breaking apart under acceleration. Higher ACC means higher CON required.

[RosenMcStern]

Both STR and CON may be interesting to use in a space opera or privateer kind of game. The same goes for relative acceleration and speed. But all this is not necessary in a Mecha game, where capital ships are basically only weapon platforms and supply bases.

On the other hand, knowing the exact position of one system on the ship may be irrelevant for a space opera game (ships might even be locationless), but is crucial for a Mecha battle, where your goal will probably be to disable that system by finding an approach angle that puts it in range of your weapons while staying out of the firing angle of the ship's main battery.

You may, of course, produce a system that lets you generate all possible information about a ship. But this implies the generation of unnecessary detail along with the necessary ones. Few genres will need ALL the details we have listed so far.

[seneschal]

But if capital ships don't have STR, how do you determine how much damage a punch or kick does when Our Heroes' craft goes all Robotech on an enemy vessel? Or what happens when we grab the enemy ship in our massive lion-ish paws just as it attempts to warp away?

Edited August 20, 2012 by seneschal

[Atgxtg]

Both STR and CON may be interesting to use in a space opera or privateer kind of game. The same goes for relative acceleration and speed. But all this is not necessary in a Mecha game, where capital ships are basically only weapon platforms and supply bases.

Depends on the type of mecha game. Shows like Macross and Gundam do use ships for more than just supply bases and weapons platforms. In fact, I would have expected ships in a mecha game to be built like other Mecha. Just big Mecha.

I don't understand your argument. Should I not do this because some people won't want it for their games? Okay, in that case you shouldn't write BRP MECHA, or anything else, since there are bound to be people who won't have a need or even a use for it. I have no use for Classic Fantasy. Nothing against the people behind it, but I don't want to play a BRP game that attempts to recreates the style of old D&D dungeon craws. But there are those who do. I'm not tellingthe people behind CF not to bother because it won't apply to most BRP fantasy campaigns.

On the other hand, knowing the exact position of one system on the ship may be irrelevant for a space opera game (ships might even be locationless), but is crucial for a Mecha battle, where your goal will probably be to disable that system by finding an approach angle that puts it in range of your weapons while staying out of the firing angle of the ship's main battery.

It might be crucial, it might not be. It depends on what the weapon ranges are and the size of the ships. In many cases the weapons can shoot father than the length of a big ship. so the exact location of a given system isn't usually important. In other cases it is. And, of course, if somebody goes into a breech in the hull, it is worthwhile to know what they just jumped into, but that doesn't neccesitatwe a detailed deck plan for every ship design.

You may, of course, produce a system that lets you generate all possible information about a ship. But this implies the generation of unnecessary detail along with the necessary ones. Few genres will need ALL the details we have listed so far.

Yup, but that holds true for any system. I'm sure BRP MECHA will produce some information on MECHA that won't be necessary in all campaigns. Looking at the sheet for Kootetsu Jeeg, I doubt the need for a size class (you already have SIZ) and an APP score (it's a machine, what's it gonna do, go to bars and and pick up chicks?).

Really, just what is and isn't necessarily is very subjective and based around how people use ships in their game. If somebody just uses the ship as a location to base adventures of, ala Metamorphisis Alpha, then pretty much all the game stats are unnecessary. I went with the ones I did for a reason, they are the ones that most GMs will need to know.

SIZ: You need to know how big the thing is so you can tell just how much junk and people you can cram into it. You may not need to know the precise size & tonnage,, but you do need to know approximate size, and an approximate relationship to other vehicles (i.e. can Ship A fit inside the landing bay for ship .

ACC/MOV, RATED SPEED: You need to know how long it takes for a ship to get to wherever it is going. Things like if Ship A can outrun Ship B are generally important. Even in MECHA campaigns. Macross would have gone much differently if the SDF-1 could have outrun the Zentradi ships. And what if it could have outrun the Zentradi Mecha?

ARMOR AND HIT POINTS: Are the way BRP tracks damage. We need to know how tough something is for combat pruposes and in case of collisions and other accidents.

WEAPONS: Also needed for combat. And in most MECHA anime the big ships shoot at the small fighters and power suits, so those stats are necessary.

Now some thingsa like STR, surface area, and power generated aren't really necessary for game play, but are for determining the limits of what a ship can do. If you just go with a point buy system, and let people buy things like armor and Speed directly, the big ships will be tougher, better armors, faster, more agile, and better armed, simply because they will have more points to spend.

Especially if you want the little ships to move faster than the big ones. Otherwise the big ships move faster because they have to most points to spend.

You need to know how powerful the engines are for a given mass, so you can find out how fast the ship can move.Likewise surface area/SIZ is important for figuring out how much of the ships tonnage will be taken up for armor. Power is needed just to know the limits for how many weapon and such the ship can operate. Otherwise some people will put near limitless firepower on their space SUV.

But, if this information is necessary to a GM, why would he bother with it in the first place? If somebody is using this, it means that they want to know some things about the ship. If they didn't, they wouldn't bother. If a GM wants to say, "The ship is like a huge disc, a kilometer across, has 25 AP, 2000 HP, and 12 laser turrets (4d8+4) spaced early around the hull." he can. I'm not going to stop them. It's up to each GM to decide what tools he needs, wants or considers unnecessary. Right?

[Atgxtg]

But if capital ships don't have STR, how do you determine how much damage a punch or kick does when Our Heroes' craft goes all Robotech on an enemy vessel? Or what happens when we grab the enemy ship in our massive lion-ish paws just as it attempts to warp away?

Well I give them a STR rating, but, playing Devils's Advocate for a moment:

-The Punch damage for a Valkyrie in Battroid mode would be based on the Batroid STR and SIZ (which Mecha have) and the STR of the target captial ship would have no bearing. It's armor rating and hit points would, as could wherever is in the section of ship that the battroid just punched into.

-As for warping away, logic would suggest that unless the Mecha is about the same size as the vcaptial ship, the capital ship's engines would be much more powerful and the Mecha wouldn't be able to stop it. Now wheather or not the MEcha can hold on or if the Captial ship breaks free would be another issue, as would how well the mecha could take the accleration if it got dragged along.

But the above assumes a conventional engtine producing thrust, and by "warping away" you mean try to fly away really really fast. If by "warping away" you mean using some sort

faster-than-light technology then the results will depend on just how that FTL technology is supposed to work. If it created a warp bubble, and does a space fold, like in Macross (Early Robotech epsodes) then the fighter just jumps along with the ship/ Just ask Min-Mei. Okayt, maybe not Min-Mei. On the other hand, something like the warp drive from Star Trek might drag the mecha along or not. Spomething like the hyperdrive from Star Wars would probably leave the mecha behind. But it more a matter of setting than stats.

[RosenMcStern]

Atg, I never suggested you do not write that rule system. Just that it will produce more details that any one SINGLE sub-genre of sci-fi will need. Having a generic process for detailing a spaceship could benefit many GMs. But not all.

This is exactly the same kind of detail I thought necessary at the beginning of writing Mecha. Now that the book is finished, most of that detail has gone into the "Not relevant, better not bother" trash bin. A lot of rule details does not survive first contact with playtest.

But it more a matter of setting than stats.

See? You seem to agree with me.

@Seneschal, your observations need an answer but it is not relevant to this thread unless we wish to derail it. I can answer in the mecha-specific thread if you wish.

[Atgxtg]

Atg, I never suggested you do not write that rule system. Just that it will produce more details that any one SINGLE sub-genre of sci-fi will need.

Probably not. I'm going to try and simplfy it as much as possible. So it probably won't provide as much detail as some Gms might want for some settings, styles of sub-genres.

Having a generic process for detailing a spaceship could benefit many GMs. But not all.

Yeah, it won't benefit or even please everyone. That's to be expected. At best it will be a useful tool for GMs who want something like this for thier SF campaigns. And for some people it might just be useful for providing some sort of benchmarks ti help them eyeball stats for their own designs.

This is exactly the same kind of detail I thought necessary at the beginning of writing Mecha. Now that the book is finished, most of that detail has gone into the "Not relevant, better not bother" trash bin. A lot of rule details does not survive first contact with playtest.

See? You seem to agree with me.

That the setting and style decides what mechanics to use (or not use)? Certainly. Although some things would probably be nearly universal. Ships would have some dimensions and mass, although the precise values might not be that important. And some things that would be important, will get glossed over too. In all the SF films and shows I've watched, I think I've seen two WCs, but I suspect that they are there somewhere on most spacecraft. Unless there is some other advanced tech we haven't been told about. Oh, except for anime. Even the good stuff tends to throw in some fan service of anime babes changing.

Pretty much anything in any RPG importance can vary depending on the needs of the GM, group, playing style, setting, genre and campaign. If I were running a Star Wars campaign, I'd go into more detail with fighters and transports, a bit less with captial ships, and cover stuff like Death Stars in only broad terms. Well, actually, I probably would go into a bit of detail for a Death Star write up. Not because I had to, but just to see how it comes out. Sometimes it's fun to see what the realistic requirements would be for something. I got a fairly decent write up of the Seaview and Flying Sub from Voyage to the Bottom of the Sea that way. It was kinda interesting to see what sort of reactor was needed to get the performance required, and find out stuff like what the flying sub,s top speed would be a sea level, it cieling and other junk like that. But most GMs wouldn't need that stuff. I certainly wouldn't expect them to go into that level of detail though. Nor require in in a design system.

Edited August 20, 2012 by Atgxtg

[seneschal]

Sheesh, I would like that level of detail on the Seaview and the Flying Sub so I could actually run a campaign!

I don't want to derail the thread. Atgxtg's reply to my quip was thoughtful, well-reasoned, the proper sort of answer a game designer and sci-fi buff should give. (Thank you, BTW.)

On the other hand, I know my players. They'd figure that since the Super Defense Fortress (a capital ship) can (apparently) morph into a semi-humanoid form that they'd take full advantage of it even if the transformation does play heck with Macross City. They'd attempt to use its giant appendages to grab the Death Star and hurl it through the cosmos like a bowling ball. (What? Yes, as a matter of fact, they do also play TOON. Why do you ask?)

Edited August 20, 2012 by seneschal

[Atgxtg]

Sheesh, I would like that level of detail on the Seaview and the Flying Sub so I could actually run a campaign!

That can be arranged. It's actually easier to stat up something from whatever "real" data exists than it is to come up with a design system or stats out of the blue. In fact, one reason why I did a little research into the real math was to help with the design rules. If you have some idea about something works it's easier to tell if the design rules work, where they don't, why not, if it is worth bothering about, and where you can cheat and get away with it.

Some of the hard bits are where game rules conflict with reality. For instance, a average male human does not (cannot) actually exert a STR 10-11 force for very long, nor does (or can) a horse. So vehicle STR scores seem a bit low until you realize that they can perform at peak levels for much longer periods of time. Although I have to admit that some parts of BRP hold up much better than expected. Human and even horse power output in BRP is pretty much on the money.

As far as the Seview and Flying Sub go, the hard bits are:

-SIZ. Jason scaled down the SIZ values for large vehicles on the table on page 273 by about 90% or so. comapred to the SIZ/weight/mass table (the latter being a bit messed up). SO deciding on what SIZ value to use is a snag. I'd like to replace the SIZ table with one of my own. It won't change any of the values between 8-88, but would continue the doublnig progression past SIZ 88. But that might not go over well.

-ARMOR- I got some ideas for tranlating armor thickness into an AP value, and some ideas for modfiers for various types of hull (HY-80 steel, HY-100, Titantium) but not enough data points to test it out. LOG(mm)*20 seems to work out for armor grade steel (1 inch=28 AP as per the BRP rules), but I'd need to see how that works out for other vehicles and big guns.

Most of the other stuff I either got or can come up with something good enough to work. Or, more actually, several sets of values that could all work.

I don't want to derail the thread. Atgxtg's reply to my quip was thoughtful, well-reasoned, the proper sort of answer a game designer and sci-fi buff should give. (Thank you, BTW.)

Your welcome, and I don't think you necessarily detailed the threat. If these rules are going to be of use to others, its good to have an idea of what they are thinking of using them for.

On the other hand, I know my players. They'd figure that since the Super Defense Fortress (a capital ship) can (apparently) morph into a semi-humanoid form that they'd take full advantage of it even if the transformation does play heck with Macross City. They'd attempt to use its giant appendages to grab the Death Star and hurl it through the cosmos like a bowling ball. (What? Yes, as a matter of fact, they do also play TOON. Why do you ask?)

Uh, that shouldn't work. A GM might allow it, especially in toon or a supers game, but assuming even a shred of reality, the SDF-1 won't have any sort of leverage to exert force against so it could throw the Death Star, even if it were strong enough to do so. And if it did, and it had the strength, the effort would most likely rip the "arms" off the SDF-1.And if it had leverage, the strength, and the structural integrity to do the job, the attempt would rip a section off the Death Star rather than move the thing.

It's like when you see Superman lift a battleship. Looks cool in the comics,. but realsitically he'd either rip an end off, or punch right through the thing like a pin through tin foil.

But if you replace the Death Star with, say, King Gomorrah...