As a veteran GM of Deathwatch, I know from personal experience that Force Fields make everyone's life miserable.  They're pretty much a no-brainer piece of equipment - you almost need to have one.  They're just too good.  They go into effect every time you're hit by an attack, they completely negate the damage from the attack,  and the chance of getting an Overload is laughably small on models with decent craftsmanship (to say nothing of models that don't Overload at all....).  As a GM in Deathwatch, it became necessary for every one of my bosses to have one just so it could survive more than one round of combat.  Now, in Black Crusade, my players have just stepped off the Chains of Judgment (from the Broken Chains adventure) and are browsing the markets of Q'Sal.  It's only a matter of time before someone thinks to roll for a Force Field Acquisition, and with four players, odds are high that at least one of them will get one.  

As GM, I see three options.

1) Do nothing.  If my players get a Force Field, so be it.

Not really an ideal option. 

2) GM handwave - it's fresh out of stock, unavailable, emitting harmful radiation, etc.

Heavy-handed and leaves a bad taste in my mouth.

3) Either place restrictions on Force Fields or re-design them.

This seems to be the best option to me, but I worry that my players will see this, too, as heavy-handed (ignoring the fact that any house-rules will apply to enemies as well...).  Some thoughts that I had on this included setting an Infamy requirement to make the fields available, making certain weapons bypass Force Fields, simultaneously increasing the field's chance to go off while increasing the Overload chance, giving Force Fields a power source that must be recharged, or creating drawbacks to using Force Fields (maybe they emit radiation?)

What are your thoughts?

PrinceOfMadness said:

I had some shielded characters in my RT game. I had a few quirks: 1 Shields are only effective if they're turned on! If left 'active for extended periods, roll for burnout (Once per hr at cumulative - 10 per roll after first hr.). Players quickly learned to turn them off when not in use. This did not make them any weaker but it did make surprise pretty important! Activating  a shield is a 'ready' action btw. 2. Shields are difficult to repair in the field. Shields that suffer burnout (For whatever reason) require specialized equipment to repair/recharge and thus cannot be recharged by simple tech priest potentia coil. 3. Shields show up on Auspex like a small blazing star! If stealth is important to your mission, don't use 'em! Thes concepts quickly made my players have to make a decision as to whether they wanted their shield to be active or not.

force fields are just a way to make fights with major enemies last longer then one round.

but one could alter the rules so they give bonus stats, like bonus armour, bonus dodge or unnatural stats (toughness or agility)

I like the idea of making the Force Fields more difficult to aquire for your players.  In the Black Crusade game that I play in it time my character time to get information on where to locate it first before I could even make an aquisition attempt.

 I play apostate in our BC campaign, and having working force field is essential to survival of my character. With TB 3 and 13 wounds, if I get hit from something with decent strenght (plasma, bolter, power sword), I die in one hit (or suffer critical damage). Taking away Power Fields from normal humans would mean swift death :P I dont care what happens to space marines :)

Force fields are a very rare, very powerful item.  They're a good item for sure, but I don't see them as being unbalancing.  Just make a note that fights will last longer if one side or the other has them, and adjust numbers accordingly. 

Also, remember that force fields can overload.  Then there's the matter of the tech-use test to repair them... after you find replacement parts.  If a Rogue Trader crew has trouble finding spare parts, with their money and contacts, then your average heretic may have a considerable bit of bother getting his fancy new personal shield to work again!

Cheers,

- V.

 The only force field rule I changed was the burnout rules. Rather than a set burnout based on quality, I based it on damage. For every point of damage the field stops it adds one to the burnout number.

Poor quality has a burnout rating of 5.

Standard is zero.

Good is -5

Best is -10

A force field which burns out will stop the attack which breaks it. I like this rule, because a field being hit by a stub auto is unlikely to break, but a lascannon or multi-melta are very likely to burn a field out.

The roll to acquire decent forcefields like a conversion field is at least -30 and if you are shooting for best quality its -50 total on that infamy roll to acquire the goods. They should by no means be easy to acquire.

 Maybe I''m the only one who plays like this, but there are some items you just plain can''t find in a market stall of a backwater planet''s flea market. So regardless of the rarity and modifiers you can''t find particular items and the rarity is just as a measure for other mechanics. 

As far as dealing with force fields, my group naturally assumed that you had to roll for your sheild after every hit as opposed to attack, despite that the rule says otherwise. What this translates to is that full-auto weapons are hellish on a shield which we felt made sense: Why should a shield have the same effectiveness of dispersing a volley of shots as dispersing a single shot► Shouldn''t the shield be tested with every impact► It made sense to our group and we find that while the shields are still really powerful and provide great survival for weak characters and nutty protection for naturally tough characters, it still was not an end-all solution and still gave the players reason to seek cover when a heavy bolter is firing at them.

 After giving considerable thought to the matter and speaking with my players, I''ve decided to make Force Fields and their equivalents one step rarer while within the confines of the Screaming Vortex.  This should help to restrict Force Field acquisitions and give them reason to enter Imperial space.  For now, I''m leaving the actual Force Field rules unchanged, although I''m considering creating rules for new Force Fields manufactured by the Dark Mechanicus that function in a somewhat more balanced manner.

PrinceOfMadness said:

You may want to look at the original force field rules from the Inquisitor's Handbook for inspiration. Essentially roll 2d10 and reduce incoming damage by the total. If you roll double ones the damage slipped through and is not reduced, if you roll doubles zeroes the field burns out, but damage is still reduced.

 I actually liked that original wording and it seemed to work fine in practice. I wondered why they changed it in the first place. Didn't seem like it was too complicated of an action that it would bog down the game. 

 Because it scales worse than the system they introduced. If you want a better field it starts to get strange. 3d10 with any double? Or just tripples? Doubles would come up more often while tripples would come up a lot less. 4d10? Even more of a disparity. With the percentage system they decided on, it's a linear scale instead.

And honestly, there is at least one device in BC that just negates shields, they run out after a certain amount of time, and in BC they only go up to 55 anyway. They're fairly balanced for the difficulty it takes to get them already.

Larkin said:

Black Industries never scaled the field rules, instead they changed how burnout worked. That kept it reasonable. If you wanted a more powerful field adding dice while keeping the double 1 and 0 rules work fine, it is a trade off between negating almost all damage and the field failing. If you really don't like the idea of scaling it with extra dice just add a flat +5 or +10 to the dice roll instead. That would represent the stronger fields just as well. The benefit of the old rules was that you could damage a target with a field, if you did enough damage. With the new field rules you can't.

Black_Kestrel said:

The old system doesn't actually represent how force fields work in 40k, which is probably one of the reasons it was changed.

 Not to mention that the original rules are far stronger in the hands of already tough opponents like marines but comparitivly weak in the hands of normal humans. the percentage rules make them even across the board.

I considered changing them to make them more like extra regenerating wounds. The protection rating of each force field would be there wounds. (refractor fields have 30 whail conversion fields have 50 for example). Each would have the equivalent of a armor rating (poor have 7 armor, common quality have 10, good are 13 best at 15.) and a recovery rate that automatically restores lost wounds at a rate based on there quality rating each round. (Poor 1D10, common 1d10+5, good 1d10+10, best 1d10+15).

Force Fields would also have there own critical damage chart which could be hit due to Zealous Hatred or just by going past there remaining protection rating.

Force Field Critical Effects (note that a Force Fields recovery rate works to remove critical damage at its normal rate but repair rolls are required to fix all lasting effects) (results 3-5 can stack with themselves reducing the force fields effects dramatically) 

Critical Damage        Effect

1                      One got Through: resolve the effects of the attack against the target rather than the Field, it dose help some though the character adds 1/2 the force fields armor rating (round up) to there armor against the attack.

2                      Flicker: The Force Field shorts out briefly and the character looses its benefits for 1 round.

3                     Force Field Damaged: reduce the force Fields maximum protection rating by 10. A successful Difficult -10 tech use test is required to repair it.

4                     Armor Rating Damaged: Reduce the Force Fields armor rating by 5. A Successful Difficult -10 Tech Use test is required to repair it.

5                    Recovery Damage: subtract 5 from the amount of protection rating recovered each round.

6+                 Force Field Overloaded: the field stops functioning until a successful very hard -30 tech use check is preformed. 

GM note: if the critical damage is very high (over 10) you may rule that the damage is too great to simply repair and that a successful infamy test may be required to acquire a new one or sufficient replacement parts.

After I wrote all that up I looked at it and think it may be too complicated and will likely stick with the rules in the black crusade core and perhaps be a bit stingy with the higher quality ones.