Does DR protects against Blunt Trauma?

[WaterAndWindSpirit]

Hello everyone.

Simple question: cyborg with subdermal armor (DR 12 vs cutting and piercing, 4 vs anything else, Tough skin modifier) and a basic reflex armor (same without Tough Skin) tanking a pistol shot for 10 damage. What happens?

Does the reflex armor tanks 10 piercing damage for 1 point of BT which is then tanked by the subdermal armor, or does the BT bypass the subdermal armor?

Thanks!

[vicky_molokh]

Originally Posted by B379

This is actual injury,
not basic damage.

DR protects against damage, not against injury.

[Mr_Sandman]

The next sentence makes me think that the intent of that is just that there's no wounding modifier from the damage type of the attack. Not that inner layers of armor, or DR advantage aren't effective against blunt trauma. I'd rule that inherent DR works against blunt trauma.

[munin]

Originally Posted by vicky_molokh

DR protects against damage, not against injury.

While I agree that in this case the cyborg would take blunt trauma injury since both DR were flexible, consider the case of flexible armor over rigid armor: say, 20 points of basic damage, and DR 20 (Flexible) over DR 1. 2 (or 4 cr) points of blunt trauma injury would get through the flexible armor -- is it not stopped at all (DR 1 does nothing to injury), partially stopped (DR 1 reduces the blunt trauma by 1), or fully stopped (no blunt trauma with rigid armor)?

[GodBeastX]

Vicky would normally be right, but Damage Resistance has it's own exception to the rules:

B.46

Subtract this from
the damage done by any physical or
energy attack after the DR of artificial
armor (you can normally wear armor
over natural DR) but before multiplying the injury for damage type.

Where as armor normally layered armor adds their DR together (So yes, adding the DR of flexible armor wouldn't help for the question), Damage Resistance advantage is actually another DR step. And Subdermal armor is based on the advantage. Therefore it would absorb the blunt trauma in my opinion. HOWEVER, I'm not sure that is the case as campaigns specifically says it is 1 HP injury.

That would make little sense to me if it wasn't the case because it would mean you would bypass the underlying DR by wearing a reflex suit. WHat I mean is imagine I have 1000 DR advantage. Not flexible. But I wear a reflex suit. It makes little sense that the 10 damage absorbed by the suit (On the outside) would cause me a point of injury.

That's why I say based on the advantage's description and the description of flexible armor, I would rule it doesn't injure you. It's likely that paragraph in blunt trauma forgot about the DR advantage.

[Varyon]

For through-armor effects like Blunt Trauma, Arcing Surge, etc, I'd argue that you should ignore the order of the armor, and simply assess the best armor's effect first, then the next best, then the next, and so forth, until you are out of layers. A 20 damage crushing attack against a character wearing DR 10 flexible armor over a DR 10 solid shell would be assessed the same as a 20 damage crushing attack against a character wearing DR 10 rigid armor under DR 10 flexible dermal armor - the rigid DR 10 would reduce damage to 10 (with no blunt trauma), and the flexible DR 10 would reduce the remaining damage to 0, but with 2 Blunt Trauma injury.

Realistically, the behavior of armor is going to depend on the order, but probably not in any way GURPS actually represents (which is why composite armor is built as a single material, rather than as multiple layers with complex workings). For example, rigid armor behaves much more effectively with a flexible backing than with a rigid one.

For upon-armor effects like ablation (due to the properties of the armor or the attack), Blood Agent, Contact Agent, etc, the order of the armor would matter.

[vicky_molokh]

I see my reply was too short to resolve things. I'll invoke a more detailed source:

Originally Posted by PK

No. Blunt trauma is injury, not penetrating damage. Injury, by definition, is the amount of hit points you lose after DR has been taken into account. So blunt trauma will never be stopped by DR.

Look at it this way. You have to resolve it all at once, so you don't have "DR 16 and DR 2" -- you have "DR 18, 16 of which happens to be flexible." So when you fall on your skull and take 15 points of damage, 2 damage is stopped by your innate DR and 13 from your flexible DR. Thus, you'd take (13/5) = 2 points of injury to the skull. If you'd been injured anywhere else, all 15 points would've been stopped by flexible DR, so you'd take (15/5) = 3 points of injury to that hit location.

You missed the line on p. B379 under Wounding Modifiers and Injury: "Note that blunt trauma injury has no wounding modifier." Wounding modifiers are applied to penetrating damage, not to injury. Blunt trauma is the latter -- it just comes right off your HP as-is.

Yes, exactly.

Originally Posted by PK

It doesn't. DR cannot stop injury. There is no ambiguity about this.

By definition, injury is after DR. DR stops damage, which is why its name is "Damage Resistance" (not "injury Resistance").

By the time you're applying blunt trauma injury, DR is no longer part of the equation.

[Mr_Sandman]

OK, that makes a bit more sense than what I had been picturing, which was that DR under armor had no chance to stop blunt trauma at all. It makes sense that standard DR can help reduce blunt trauma, but flexible or tough skin won't have an effect on blunt trauma. I also forgot that treating blunt trauma as injury also takes away the multiplier for hit location, not just attack type, which also makes a difference. Thanks for the post from PK.

[vicky_molokh]

Originally Posted by Mr_Sandman

It makes sense that standard DR can help reduce blunt trauma, but flexible or tough skin won't have an effect on blunt trauma.

It doesn't reduce BT, it just doesn't generate it in the first place (outside falls, where all external DR is treated as flexible). That's not the same thing.

[Mr_Sandman]

Right. I didn't mean reduce it after it was generated. It lowers the amount of damage that can translate to blunt trauma.