Spaceships 3D - suggested changes

[Alfa]

GURPS Spaceships provides rules for combat in space. There are a couple of things that I find strange or not "universal" enough, I found one thing particulary problematic: Space is abstracted to be 2D.

So I try to fix it in the following.

Please note that the "fix" is not generic, but suited for a particular setting I had in mind. Feel free to suggest changes, both inside the setting and for others. I did not read /watch a lot of science fiction, so there were not many places from which I drew my ideas, mostly, they are (in that order) David Weber's Honorverse, the Mark Brandis books (that's a mostly forgotten very old German SF series), Star Trek and Star wars. (You can add 40k to that, but I don't think this is influenced by it that much) Therefore some of my ideas might be seen as blatant rip-offs (since they are). I do not strive for originality, but for interesting space combat.

I hope that I will add a sample 3D space battle or two eventually.

English is not my native language, so please excuse my mistakes and tell me if I wrote something which is difficult to understand.

The main ideas of this fix are:

- Space should be 3D - at the moment we have a 2D approximation in G:SS3 and the somewhat unintuitive rules in G:SS1. This is the main point of this post. Everything else is secondary.

- Maneuvring should matter - that is a point G:SS3 does mostly right, but it should be even more important in 3D

- Ships should survive a fair bit of punishment (I know this is more Space Opera and not very realistic) - G:SS admits the "eggshells armed with sledgehammers" problem, but the fixes are not completely satisfactory.

- Missiles should be challenging, but not "one missile kills one ship", as it is at the moment. There should also be an incentive to use bigger missiles. At the moment a tertiary battery missile can kill a ship of the same size modifier: EG a SM+7 ship can fire thirty 16cm missiles from a tertiary battery that deal an average of 880 dHP of damage...each. The ship itselff has a whopping 50 dHP. For a SM+15 ship the relation is slightly better: 64cm missiles do 3.360dHP damage on average, for a ship that has 1.500 dHP. Armor and screens mitigate that to an extent, but still, just a couple of tertiary missiles can destroy a ship of the same class (note, that even the small ship can seriously cripple the big with just a couple of hits)

- Related to the above: Point defense against missiles should not be a coin toss (either destroy ALL missiles or be destroyed). "Missile Shield" arguably makes this problem worse, since (slightly simplified) in a 3-minute turn 30 rapid-fire towers in a tertiary battery can destroy 3000 incoming missiles, but you are pretty screwed when the enemy shoots 3100, and if the enemy can shoot 3000 missiles he probably will walk the extra mile and shoot a couple more. PD saturation should be a viable tactic, but not like that. Even worde, if you go up to improved VRF-towers (60k shots), the enemy will need to use a three-digit number of turns just to launch all the necessary missiles (that is, if using a "torpedo boat", which has only the bare necessities for maneuvring and JUST missiles everywhere else, including a considerable reserve in storage), making missiles nearly absolutely useless.

- Lasers&co. are almost good as it is, but I feel strange about the ranges - shouldn't each increase in energy be equally rewarding? Reach is my strongest concern: At the moment, there is little incentive to build a spinal weapon on any ship but a SM+6, SM+9 etc, since on all other ships the upgrade from Major to spinal only gives a (moderately decent) damage boost, but no increase in range - and uses three times as much modules. It just seems better to build three Major batteries . Meanwhile for SM+6 ships the increase from Major to Spinal doubles the range and gives the damage boost.

3D:
There are a couple of ways to create a 3D map.
The easiest way would be with squares and counters which denominate height, but that is more D&D than GURPS and i found it pretty goofy that you are always faster if you move in a diagonal.
So there shall be hexes. Again, the easiest way is to create a hex layer and denominate height, but I still am uncomfortable with that. Why should the z-axis be inherently different from the x and y?

The solution is to crete interlocked hex layers. On the board table below (which I built with Tabletop Simulator) I use the colors black, grey and white. Grey hexes stand for all layers which are multiples of 3: 0, 3, -3, 6, -6 etc. White hexes stand for all layers which are multiples of 3 plus 1: 1, 4, -2, 7, -5 etc. Black hexes stand for all layers which are multiples of 3 minus 1: -1, 2, -4, 5, -7 etc. Always note which layer a given object is on!

https://ibb.co/n46h6K

Any given hex has 12 adjacent to it, for example a black hex (EG layer -1) has: 3 white ones "below" it (Layer -2), 3 grey ones "above" it (Layer 0) and 6 black ones on the same layer. In the 2D representation these last ones are connected by the diagonals. It takes a little bit of time to get used to it, but you can work with that.

Fun fact: apparently, the figures the hexes represent are dodekaeders (d12s), but not perfect ones - they need to be slightly adjusted to interlock.

Ship facing:

Before we continue, please note that I use a somewhat other ship design than G:SS suggests. The basic components are the same, however I use a lot more sections than suggested. These are: Core (C), Prow (P), Stern(S), Left (L), Right (R), Top (T) and Bottom (B). Please note that using nautical terms such as Port, Starboard etc. would complicate the letter codes. Space is not necessarily an ocean...
I use the following design: the spaceships will have one prow and one stern hex, two left and two right, three top and three bottom. I use counters in the colors blue for P, yellow for S, red for L, green for R, white for T and black for B.
The following three basic facings are possible:

[Picture]


The first one is the easiest: the ship flies in the main "plane". Of course, it can be flipped by 180°, thus flying "belly up".
The second one is slightly more complicated; the ship still moves "horizontally", but its side faces up (here: left). Again, it can fly with its right side up, its the symmetrical opposite.
The third is a ship "diving", in this case "down". Note, that this facing has eight variations: L to the left and front, L to the left and behind, L to the right and front, L to the right and back; and the same four for "diving up".

In each case it is enough to mark (for example) the prow and the left hexes; the rest can be determined from that.
To determine which hull section is facing a given object, draw imaginary lines in each of the twelve directions around the ship and see to which of those it is closest. Do not forget to count layers. If it is equally close to two lines of two different sections, I suggest to use the following rules: T&B take precendence over R&L, which again take precendence over P&S. Alternatively, rule that thus it faces both (or all three!) of those and thus can be on the receiving end of double (or triple!) the firepower.

To be continued - I will post my further ideas if somebody is interested.

[Ulzgoroth]

Originally Posted by Alfa

- Space should be 3D - at the moment we have a 2D approximation in G:SS3 and the somewhat unintuitive rules in G:SS1. This is the main point of this post. Everything else is secondary.

SS3 isn't really approximating, it's just not using the Z axis. In many cases that really is not a problem, because maneuvering out of the plane has surprisingly limited usefulness. Still, there are reasons to want to be able to model it.

Originally Posted by Alfa

- Lasers&co. are almost good as it is, but I feel strange about the ranges - shouldn't each increase in energy be equally rewarding? Reach is my strongest concern: At the moment, there is little incentive to build a spinal weapon on any ship but a SM+6, SM+9 etc, since on all other ships the upgrade from Major to spinal only gives a (moderately decent) damage boost, but no increase in range - and uses three times as much modules. It just seems better to build three Major batteries . Meanwhile for SM+6 ships the increase from Major to Spinal doubles the range and gives the damage boost.

Breakpoints happen. Certainly in mapped combat you could have a bit less than by the book by interpolating range variation smoothly rather than the existing practice of sticking to (vaguely) round numbers.

Originally Posted by Alfa

So there shall be hexes. Again, the easiest way is to create a hex layer and denominate height, but I still am uncomfortable with that. Why should the z-axis be inherently different from the x and y?

The solution is to crete interlocked hex layers. On the board table below (which I built with Tabletop Simulator) I use the colors black, grey and white. Grey hexes stand for all layers which are multiples of 3: 0, 3, -3, 6, -6 etc. White hexes stand for all layers which are multiples of 3 plus 1: 1, 4, -2, 7, -5 etc. Black hexes stand for all layers which are multiples of 3 minus 1: -1, 2, -4, 5, -7 etc. Always note which layer a given object is on!

Interesting scheme, but as you say it's a bit confusing. And the z-axis is still inherently different, since distinguishing between 3 and 0 has to be done by a counter rather than by actual map position.

If it works for you and whoever you intend to play it with, go for it, but...a hex map plus z-axis seems simpler to me.

Originally Posted by Alfa

Ship facing:

Before we continue, please note that I use a somewhat other ship design than G:SS suggests. The basic components are the same, however I use a lot more sections than suggested. These are: Core (C), Prow (P), Stern(S), Left (L), Right (R), Top (T) and Bottom (B). Please note that using nautical terms such as Port, Starboard etc. would complicate the letter codes. Space is not necessarily an ocean...
I use the following design: the spaceships will have one prow and one stern hex, two left and two right, three top and three bottom. I use counters in the colors blue for P, yellow for S, red for L, green for R, white for T and black for B.

It kinda sounds like you're trying to re-invent Attack Vector: Tactical. Which isn't a bad thing as such, but you might be interested in looking at what's been done...

[Alfa]

Originally Posted by Ulzgoroth

In many cases that really is not a problem, because maneuvering out of the plane has surprisingly limited usefulness. Still, there are reasons to want to be able to model it.

This is one of the things I want to test - starting with four participants in a fight 3D should actually kick in from a mathematical point of view; i think an encounter between five or more ships or more will actually gain a lot from a tactical point of view if in 3D.

Originally Posted by Ulzgoroth

Interesting scheme, but as you say it's a bit confusing. And the z-axis is still inherently different, since distinguishing between 3 and 0 has to be done by a counter rather than by actual map position.

The scheme I use here is, in my opinion, better than just 2D+z-Axis, since now any direction the ship is facing is similar from a geometrical perspective (especially angling the spacecraft seems strange - it will suddenly "lose" right/left and "gain" top/bottom hexes if rotating by 90°.)
Also, I would argue that the difference is not "inherent", but merely in the way the field is viewed. By careful calculation you can rotate the field to the "side" and still get a hex map - something 2S+Z-Axis will never produce.

Still, case in point: the z-Axis is indeed simpler.

Originally Posted by Ulzgoroth

It kinda sounds like you're trying to re-invent Attack Vector: Tactical. Which isn't a bad thing as such, but you might be interested in looking at what's been done..

I don't know that game. Likely there will be a couple of worthwhile things to read, but I'll try to keep it in the GURPS framework, and it might be more consistent with GURPS if I don't start with shoehorning other games into it.

[acrosome]

You sound like you want to play Children of a Dead Earth...

:)

[Alfa]

Ship design:

I am using mostly TL 10 stuff, but also a fair bit of superscience and a little bit of TL11.

I liked the idea in the Honorverse that a ship is protected from certain sides but vulnerable from others.
This is heavily space opera, and you may come up with other ideas to give sides "identitities" or just throw it all of the airlock and decide that "side identities" are something for romantics.

So, the idea i am working with goes like this:
Ships are shaped more or less like bricks with rounded corners (or somewhat more aesthetical if you wish); P&S relatively slim, T&B relatively broad. Thus, P&S have four modules each, L&R five each; T&B six each. In addition there are six modules for the "inner core" (C) of the ship, and four more core modules can be place freely (except in the "inner core", it's cramped enough there). I know that this is strong upscaling, but it gives us a nice total of forty modules; thus, exactly two times as much as normally. I will double the tonnage of the ship without altering its size modifier, its complicated enough as it is.

Since there are more module, a module is disabled on a hit of 5 to 25% of the whole vessels dHP, destroyed on up to 50%. Anything above 50% (or 25%, if the system was already disabled) carries over to the next system. If a system has fewer than 6 locations, reroll numbers above that number, otherwise use the rules as in G:SS1.
Treat the C section as a core section for all the others; however, to reach it, you'll need to go also through the core modules in that side. It might be a good idea to put your powerplants, ammo and maybe your commander in there. The inner core can be armored! This Armor protects the C modules, and the C modules only.

Furthermore, we're talking about space opera here, so we add survivability, in form of dHP. The basic formula in G:SS1 is "third root of mass times seven". I think somewhere in Pyramid it was suggested to use the square root instead. I also use a multiplier of ten after that. To make small craft a viable choice against something larger, I'll add a flat of 100 points to any ship (that's not very GURPSy, but it seems to work).

dHP = 100+10*tons^0,5

For a SM+10 ship (now: 20.000 tons) it gives us approximately 1514 dST/dHP. That is not that much more than the average 880 dHP-damage of the tertiary SM+7 launcher noted above, but it gives us a better starting point. Its also a big (actually: tenfold) step up from the 150 dHP given for SM+10 in G:SS1.

Back to the sections. In my setting I shamelessly rip off the Honorverse, and give T&B a mandatory heavy force screen , which must occupy a module in each of those sections. It also always should be in up-powered mode. The screens protect only from the sides they are facing. Screens are TL11^, and to compensate for this, I use a screen for a ship one size smaller. Since they protect only a part of the vessel, i halve the cost and the used power points (thus: always 1 per side). And to discourage ships with high damage output from still targeting from this side (and hoping to circumvent the DR), any attempt to hit the ship from this side is at -15. A freak hit might come through, just don't count on it. Also, you can't fire through your own screen - this can be a disadvantage.
Also, T&B will be the locations of the drives. I use reactionless drives, TL10 version, cold and hot variants (i multiply their g-output by 1.25 - this gives better movement on a 1.000 mile - 3 minute map)
If the screens crash down for whatever reason, an attacker is at +2 to hit them, at -2 to hit R&L and at -3 to hit P&S.

The sides R and L will be the "standard fighting sides", thus giving no boni or mali to hit them. T&B are at -2, P&S at -4 to hit from this directions. You can have light force screens here. Again, 1 SM down, cost halved, protects one side only, half the energy points (0.5 - I am not sure how to deal with this . Maybe some other systems can also go to "half power"? Would make sense for batteries with "off" facing - they get only half the RoF). However, you can shoot through it. In addition, it gives a -3 to hit as long a it is up (thus, complicated but not unsurpassable, and these two properties make it attractive to position it towards the enemy).

P&S can absolutely not have force screens (thus, use armor if possible!). Attacks are at -1 to hit there, T&B at -3, R&L at -4. Note, that as long as the side screens are up it is easier to target the sides from the front and back, so a ship should avoid to show its throat if possible.
This creates a couple of interesting tactical choices. First, you may try to keep a stronger opponent in your T&B directions, while waiting for an edge or trying to escape. Second, your R&L sides offer you a lot of protection, while also allowing you to fire, so that would be the optimal "fighting position". Third, showing your prow or stern is only viable if your side screens are disabled or if you want to ganble and fire your spinal weapon, thus, accelerating straight towards your enemy is usually not a very good idea. Fourth, since all the above also applies to missiles (as in being attacked by them), a ship can be forced into a position where it needs to make the choice - either give the missiles or their ship a shot.

[David Johnston2]

As it happens I have personally played tactical ship combat with an operational Z axis. It was an exercise in pointlessness as long as you were in deep space. provided that you don't have a system where ships are liable to be more vulnerable to attack form the top or the bottom. Of course combat in orbit around a planet is a whole different deal, and really freaking hard to model.

[Alfa]

Originally Posted by David Johnston2

As it happens I have personally played tactical ship combat with an operational Z axis. It was an exercise in pointlessness as long as you were in deep space. provided that you don't have a system where ships are liable to be more vulnerable to attack form the top or the bottom.

I suspected that much - exactly for that reason I use the differently "screened" sides. That should make 3D maneuvring more challenging. However, it might still turn out pretty pointless.

Originally Posted by David Johnston2

Of course combat in orbit around a planet is a whole different deal, and really freaking hard to model

I am still writing the stats, but i work with the idea that the combat to which I hope to come eventually will involve at least a moon. It isn't even that hard to determine (especially on a 1000-mile-scale, it will likely occupy up to 13 hexes in a "ball"); gravitational pull is slightly more complicated

[Ulzgoroth]

As this goes on, I think the suggestion that you look at AV:T or maybe Squadron Strike by the same designer seems more fitting.

I've not actually examined it, but AV:T does have handling for orbital action, for instance. (AV:T has the problem of being tied to a specific setting and not providing any design system. Squadron Strike from what I know of it may be a bit more abstract than you want.)



One place where a third dimension is really important is evading a scatter pattern. In 2d, your evasive space scales directly with how far you can dodge, in 3d it scales with the square.

[Humabout]

I think its worth noting that Roger and I addressed your concerns regarding weapon damage and spaceship toughness in So You Want to Build a Spaceship... in GURPS Pyramid #3/95 - Spaceships.

[weby]

On 3d combat: we have played with 3d combat and as said above it is mostly useless. The only real exception is in a fight with lots of fighter type craft with only forward firing weapons, in 3d combat it is much harder to give mutual support to stop others from flanking.

The system we used was have the three vectors(X,Y,Z) of each ship as separate number on a spreadsheet. The spreadsheet also had the formulas for "I want t change my vectors by amounts A,B,C: how much thrust do I need to apply" as well as a "where does to nose really point" information. Then we used a hex map with a counter indicating Z position from the plane of the map.

It worked fairly well, but was quite cumbersome and did not really give anything in most cases, so mostly we just used 2d maps.