We are thinking about changing the rules for Force Fields in our Rogue Trader RPG as we see some problems:

  • The percentage is rather cumbersome and adds a lot of rolling dices during the combat.
  • The "complete or no" negation is an issue. With that kind of rules, a Force Field can completely negate the shots of tanks or even titans for several rounds, specially the stronger fields like the Eldar Force Field with a shield rating of 75.
  • It doesn't really match with the fluff. Goge Vandire had himself shot and was protected only by a force field, a risk he'd probably not have taken if the Rosarius only had a 50% chance of stopping the shot.

Has anybody created house rules for those shield in order to address these issues? I've found a discussion in the FFG forum and there are some interesting suggestions but in the end, they all lack of the problems mentioned above.

We've thought about a fixed number of hit points for each shield but a member of the party is not happy about that. I therefore thought somebody here might have an idea on how to solve the issue. Suggestions from other systems using force fields are also very welcome.

  • \$\begingroup\$ Rule-wise, force fields of all kinds have always been hit-or-miss chances, even long before they created an RPG from the tabletop game's lore. There has been lots of fluff written and I guess it's inconvenient for story tellers to have a random chance effect in their stories. Too much ex-machina if it works and much ado about nothing if it doesn't. But through all the editions, in all 40K games, force fields have always been something that might save you if you are lucky, but certainly nothing to gamble your life on if you don't have to. \$\endgroup\$
    – nvoigt
    Jan 28, 2021 at 16:23
  • \$\begingroup\$ It might save you from a tank round one moment, but it might fail you when a snotling with a rusty knife jabs at you the next. \$\endgroup\$
    – nvoigt
    Jan 28, 2021 at 16:23
  • \$\begingroup\$ @nvoigt In the fluff, it's often "we need more firepower to bring those shields down". Rules wise, rolling against a value is rather easy. The thing is, a Dark Eldar Archon with a Shadowfield (shield rating 90) is basically invincible, it's a lot better to use a dozen goons with some a lasrifle to bring him down than an emperor titan levelling the whole area he's standing on. Even with a rosarius, I have a 50% chance of survivng without any further issues a titan plasma weapon to the head. \$\endgroup\$
    – Shade
    Jan 28, 2021 at 16:50
  • \$\begingroup\$ The "more firepower" is mostly used against vehicle powered shields, that indeed work by refreshing or restoring power after getting hit, so hitting them with bigger and more rapid firing weapons is a plus. Personal force fields have always been a lucky chance, and depiction in fluff to the contrary is just wrong. That said, I am on your side, I'd rather play a game where I can make a decision to pool resources and bring a shield down instead of rolling dice and hoping for blind luck. All I'm saying is: do it because it's more fun to you, not because the fluff says so. The fluff is wrong. \$\endgroup\$
    – nvoigt
    Jan 28, 2021 at 17:15
  • 1
    \$\begingroup\$ @nvoigt We're now on rank 10 in RT and our enemies have similar equipment as we do. Combats already take a long time and with the force fields we / our enemies have, it basically get impossible to hit after parrying etc. So, we're often occupied for dozens of minutes simply attack / parry / shield / until we finally hit... then, we have good armour and take basically no wounds.... Fluff is only one reason. Most of us don't like the (yes, very extreme) idea of somebody being able to survive continuous fire from heavy vehicles like tanks and so on without having to worry about it. \$\endgroup\$
    – Shade
    Jan 28, 2021 at 17:22

1 Answer 1


First of all - do not discount original force fields so quickly.

  • While they may look cumbersome when taken as is, they actually are pretty lightweight (just 1 simple percentile roll per hit) in comparison to other options. For example, the first force fields, described in Dark Heresy supplement - Inquisitor’s Handbook worked like this:

This amulet functions as a force field. Any time the wearer is attacked, he may roll 3d10 and reduce the Damage dealt by the sum of the dice. Should the wearer roll double ones, the attack bypasses the field completely (do not reduce the Damage). If the wearer rolls double tens, the field overloads and shuts down for 1d10 Rounds. In the case of an overload, the wearer must roll an extra 1d10. On a result of an 8, the amulet is burned out and cannot be used again.

  • Complete hit negation it’s up to the GM. If the attack power is too high - he can just say that field couldn’t protect wearer from death (time to burn Fate Points!). Or that force field negate most of the attack’s power (leaving wearer critically damaged) but gets destroyed in process.

  • And don’t forget about overloading. A Dark Eldar Archon with Shadowfield can ignore a number of shots, but then he rolls a low number, and suddenly his force field just turns off, leaving poor bastard exposed to angry PC-s (to add some fun, overload rating of such device could be even higher than on crude Imperial force fields. After all, Dark Eldar don’t mind doing a little bit of sabotage even to their own kin). Also you can raise an overload rating for hits delivered by some heavy weaponry.

But, if you are strongly inclined to use more “fluff”-y force fields, you probably need the rechargeable shield concept.

In such a concept, your force field has a number of “hit points” but it’s not fixed. Instead there is a maximum value. You can restore field’s HP by a number of ways, for example:

  • Regeneration - a force field could slowly restore itself. There could be various types of force fields - some have a really good HP pool but a poor or no regeneration rate (so it will be pretty useless in a continuous battle), while other can fully recharge themselves in a few rounds, but for a cost of maximum HP value (so a concentrated assault could quickly overrun such a field).

  • Recharge by some energy source, like generator, or powerful battery (power armor energy source, for example). Requires a successful Tech-Use test with at least -20 difficulty, so it would be wise to leave such a task to a techpriest.

  • Luminen Charge - requires a techpriest (obviously)

  • Full recharge and repair - requires some heavy machinery, powerful energy source and qualified tech assistance. A Rogue Trader ship should have all of this.


Optional rules - As force field is a first line of defence, Armor should not affect damage dealt to field HP. This leaves high-Penetration weapons slightly ineffective. To fix this, you can either:

  • Give a field its own armor-like damage reduction negated by weapon Penetration. This can further increase force fields variety - those with high damage reduction will be much more effective against high numbers of lesser enemies


  • Simply add Penetration to weapon Damage when hit a force field.

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