VBAM Games Forums

Gunship & Anti-Fighter

I decided to look at the cost effectiveness of Anti-Fighter (AF) and Gunship (GS). The first thing I did was calculate percentages for attack rolls, the d6 + readiness modifier (which ranges from -6 to 6). Added together these get a range of -5 to 12, assuming no other modifiers from race in Menagerie, or officers from Those Who Serve, or elsewhere. Here is the percentages each number came up:

-5 0.154%
-4 0.463%
-3 0.926%
-2 2.315%
-1 3.549%
0 4.630%
1 11.883%
2 14.815%
3 14.506%
4 13.426%
5 12.654%
6 11.883%
7 4.630%
8 1.389%
9 1.235%
10 0.926%
11 0.463%
12 0.154%

Modified to 0 to 12 range, and divided by 10 (final step in combat calc) you get the following percentage of AS, and the percentage that that number will come up

0% 12.037% (sum of -5 to 0, since you can't do negative damage)
10% 11.883%
20% 14.815%
30% 14.506%
40% 13.426%
50% 12.654%
60% 11.883%
70% 4.630%
80% 1.389%
90% 1.235%
100% 0.926%
110% 0.463%
120% 0.154%

So, now we can analyze AF & GS. I will use AS & GS in the calculations, but you can substitute PD for AS and AF for GS to get the AF analysis.

First lets look at the current costs (I assume that 1 AS is 1 Mass Cost, since I don't find that in the current playtest rules).

1 AS = 1 GS in terms of Mass Cost - 100%
To analyse this, you have to look at how often you are going to get 100% value out of your AS (GS will always give 100% value)
100%-120% is the range where AS gives as good or better than GS, and the total % of the time that comes up is 1.543% of the time. So, 98.457% of the time GS is the better value.

2 AS = 1 GS (GS is Mass Cost: 2) 50%
50% to 120% range where AS is as good or better, which comes up 33.333%, meaning that 2/3 of the time, GS is still the better value.

3 AS = 1 GS (GS is Mass Cost: 3) - 33.333%
40% to 120% range where AS is better, which comes up 46.759%, meaning that GS is still the better value coming up 53.241% of the time.

4 AS = 1 GS (GS is Mass Cost: 4) - 25%
30% to 120% range where AS is better, which now comes up 61.265% of the time, meaning only 38.735% of the time is GS better.

So, it is only at GS with a Mass Cost of 4, does AS become the better value in Space Combat. Now, this does not take into account other uses of AS, such as in bombardment, but I would at least triple the cost of GS (and AF) AND place a limit of maybe 1/4 AS rounded down as your max GS.

Speaking of Bombardment...

Bombardment

This special tech is not quite as useful as Gunship and Anti-Fighter, but it is still way too cheap, especially since it allows WMD's to be used.

Here is the relevant section from the playtest files:

The number of bombardment points available to a task force is calculated by totaling the bombarding units' Attack Strength (AS) and Point Defense (PD) values, multiplying the total by the result of a D6 roll, and then dividing the result by 10. Round fractional bombardment points to the nearest whole number. A task force with 14 AS and 18 PD that rolled a '4' on their D6 roll would have (14 + 17) x 4 ÷ 10 = 12.4, which rounds to 12 BP.

Units with the Bombardment ability are dedicated to the task of bombarding enemy positions, and they add a bonus +1 BP to their task force's total per point of Bombardment rating they possess.

So, in this case bombardment factors is calculated as: (AS + PD) * d6 / 10. The d6 / 10 gives us a range of 10% to 60% of (AS + PD), giving us the following table

%AS+PD % of time
10% 16.67%
20% 16.67%
30% 16.67%
40% 16.67%
50% 16.67%
60% 16.67%

Again, assuming AS & PD have a Mass Cost of 1 each (not listed) and Bombardment being listed with a Mass Cost of 1, this gives us the following analysis

1 AS or PD = 1 Bombardment - 100%
This means that since AS and PD are never more than 60% effective, that in this case Bombardment is more valuable 100% of the time.

2 AS or PD = 1 Bombardment (Bombardment Mass Cost: 2) - 50%
50%-60% is the range where AS/PD are better, coming up 33.333% of the time, meaning that 66.667% of the time Bombardment is better.

3 AS or PD = 1 Bombardment (Bombardment Mass Cost: 3) - 33.333%
40%-60% is the range where AS/PD are better, coming up 50% of the time, meaning that only half the time Bombardment is a better value.

As I said at the top, Bombardment is not as valuable a special tech as Gunship, since it is limited to a specific application, but, I would at least double the cost, since it does allow the use of WMD's. Especially since an empire might develop a ship strictly for bombardment, it should not be limited to a percentage of AS/PD.

What about having a Special Tech of Engine? This would represent the engines in normal space (as opposed to FTL). I figure that the size would be about equivalent to FTL drive (Mass Cost: 50% x Construction Cost).

Now there are 2 options that could be used here.
1 - Assume that this is an advanced drive over the basic drive, and that if you do not have this tech in your ship, it is assumed to be Eng-0.
2 - Require all ships to have an engine rating of at least 1, thus space stations & satellites would be at Eng-0.

Why would we want to create this special tech? There are several reasons.
1 - Tactical Games generally have a engines of different ratings, and this would give some meaning to it in VBAM.
2 - In future expansions, such as Campaign Companion with the Admirality System Generation, this would allow different speed movement between worlds in the system.
3 - It could be used to modify Pursuit Scenarios where differences in TF speeds could lengthen the scenario (if pursuer is faster) or shorten it (if the pursued is faster) by up to the difference in speeds.
4 - It could allow formation bonuses.

Now, reasons 3 & 4 would depend on the slowest Engine Rating in your Task Force (#3) or Squadron (#4).

For reason 4 above, Formation Bonuses would depend on if Engines are required in the game or not. If they are not required, I would assign Formation Bonus to a squadron based on the SQRT(Eng) (round down) of the slowest ship in the squadron.
If Engines are required, I would assign Formation Bonus to a squadron based on SQRT(Eng) - 1, round down. This would actually give space stations and satellites a -1 to formation level, which kind of makes sense, since they are unable to move and jink and dodge.
Remember that Engine Rating would be halved when crippled.

Another later tech advance would be Anti-Grav Engines (Mass Cost: 20% x Construction Cost), which would have a prerequisite tech advance of Anti-Gravity.

Some interesting stuff to think about. Thanks for doing those calculations, as a game designer (Hobby, not vocation), I always learn stuff reading these boards. It's always nice to have hard math on your side, hehehe. The VBAM crew seem to want to do 2E right so, unless they have other reasons to keep things as is, I'm sure they will consider your Analysis and if judged as correct (or even - "more correct") they'll add to 2E [If they have the time, Doctor; if they have the time].

Jimmy, thanks for doing the math (so I don't have to!). That saves me some time as I knew I was going to have to sit down and pound the numbers for those costs at some point. Excellent! I have just made the recommended changes in my working draft.

As for the Engine stat, I had one in an earlier iteration of the rules and it was used to determine the number of formation points a force had to purchase formation level upgrade. That capability has since between merged with Command to give Command more importance. That being said, I like the idea of having an Engine component in the rules, and I think you have hit on the way to make that work. If called Fast or Speed, I think the best fit of the ideas you provided would be the Pursuit scenario length modifier, movement in CC, a retreat bonus (cumulative with FTL), and a formation level bonus equal to the formation's lowest rating. That would give players an additional reason to build squadrons of small, fast attack ships, as they would be harder to hit on their own, freeing up points to increase formation levels elsewhere.

Baseline speed for all non-starbase/installation units would be 1, with each point of Engine/Speed rating increasing this by 1.

Great ideas!

I like the idea of an Engine tech, if only because I like to see a definite split between Tactical and Strategic unit abilites. This would place Command squarely into the latter....

Cheers
Mark