Phoenix Space Combat System for Dummies - Part Four The Probability Engine

the 'force' does not impact the probability engine in Phoenix though you can have cool space fighters and bombers.


Up to this point in this series of short combat articles we have been dealing with relatively set figures. For the next section we need to have some understanding of bell curves and probability. Now this is absolutely not needed to have a basic understanding of Phoenix naval combat so this is one article I only encourage those who are really interested in the system to read (or alternately you might understand it already without extra information..)

Anyway if you are still here Phoenix uses a 3d6 probability engine for random figure adjustments. This basically means it generates a bell curve which is really, really prevalent in the world and the result will sit somewhere on the bell curve 1. Now this is simple enough to view.

If you roll a single dice the odds are obvious - you have a 16.66666666666667% chance to get any of the dice faces (allowing the dice is perfectly balanced and thrown correctly). If you throw two dice then the odds start changing and can be represented in a chart.


Total of 2 dice

Now admittedly even the most common result of '7' is only encountered 16% of the time but put this in a bell graph and it is 'almost' a bell the reason is isn't is that we are not far enough from the linear single dice and need a third to make a more

Take a chunk out of the highest probability roles (so draw a line at the combination 4 results count and you pick dice rolls between 5 and 9) and the probability is 64%. Even totalling the chances of rolling 6,7 and 8 gives you a decent probability of 42%.

When we add in 3 dice the bell curve becomes more pronounced and though the number of results is higher the chances of rolling average are actually better as the extremes become less likely.

Here is a simple chart not showing the (larger amount) of possible combinations

Total of 3 dice






If we transfer this to a chart you can now see we have a true bell curve in existence.

Now Phoenix uses the 3 dice system to handle random blocks to damage. So when you shoot a beam laser weapon this involves armour/scintillators and shields. Each of these 'might' block all the damage or it might block none. 3

Anyway the likelihood is that it will be high on the bell curve and block an average of the damage most likely between between 40-60%. The more attacks that are launched the more the chances of the damage blocked (or not blocked) will reach the top of the bell curve the less attacks the more likely that damage blocked/not blocked might be extreme/not extreme. This is a simple function of probability over time and if this interest you this article here (involving testing actual physical dice for a WW2 boardgame for accuracy) covers it quite well. Dice Probability (hulldown.co.uk)

When making your own damage test programs/spreadsheets you can assume (roughly) that with average luck a mean 50% of blockable damage will be blocked. So If you had 80 armour then it *might* block 80 damage but it also *might* block as low as 0 damage but is most likely to block between 30-50 damage and assuming 40 will even things out over time.

Not all things 'use' the probability engine. But those that don't tend to not use probability at all - we will cover these as we find them.

There. Now we can move to actually damaging something. Next up we will take a quick look at all the defensive layers before moving through each one by one and seeing what the related battle report looks like.




1 Bell curves are an important design tool in society. For example if you do a graph of adult population 'height' then this also is an accurate bell curve with (say) the smallest people will be on the left and the tallest on the right with )say) those at 5' 8'' right at the top. The higher up the chart you go the more common the height. Now I said this is a design tool. If you were making (say) a chair you would draw a line across the chart at a specified level (say 10 % up) and then you design the chair so anyone above the line would find that chair comfortable and anyone below would not. This might sound cruel but its not as (for example) imaging making a chair for someone who is 3' tall. Now imaging someone at the other end of the bell curve at 7'2 trying to sit on that chair. It would not 'work' so this calculation basically ensures that the majority of designed articles fit the maximum spread of the population possible. Those at the extremes would have to get bespoke furniture to better fit their needs. A company might design to match (say) the 3' - 5'2 population but they would then lose vast numbers of sales due to the much larger amount of the population who would find it uncomfortable. The same applies to weight, clothes ranges, car seats - most things you can think of.

2 For those wondering the amount of available rolls for two dice is 36 and the calculation is a simple % generation from that. The reason 7 is the average is because you can never roll '1' with 2 dice but can roll '12' hence the higher common value. Mathematicians will be able to explain this better.

3 Phoenix appears to adjust the number so each of the three random numbers generated is 0 to 5 (this allows no damage to be blocked whereas using actual 1-6 dice values would mean you never get nothing blocked) 

I always thought Battlestar Vipers were as cool as X-Wings anyway.