Cheap armour? what's the drawback?

[Anthony]

Originally Posted by Varyon

Depends on what armor you're looking at how good/bad of a deal it is. Consider Light Plate, and applying the rules for Heavy Plate (which is how Medium and Heavy Plate were generated, this just lets you do it freeform). A DR 3 iron plate cuirass is $1000 and 8 lb. A DR 3 cheap iron plate cuirass is $600 and 12 lb.

Arguably it's $900 -- +50% for DR +1, -60% for cheap (the heavy plate rules are dysfunctional for several reasons).

[Varyon]

Originally Posted by Anthony

Arguably it's $900 -- +50% for DR +1, -60% for cheap (the heavy plate rules are dysfunctional for several reasons).

Heavy Plate isn't a +0.5 CF, and for good reason. Otherwise, you'd be looking at $600 off for being cheap for all thicknesses of plate armor - but with scale armor, for example, it varies depending on what thickness (because it doesn't follow the heavy plate rules). Honestly, I'd say the issue here is less with the heavy plate rules and more with Cheap being a static -1 DR but a price multiplier (a below-1 multiplier, but a multiplier nonetheless). Cheap being the same level of protection but with a weight multiplier would make that issue go away. Off the top of my head, something like -60% cost (as it is now) and +50% weight might work - that matches with how DR 3 plate works currently.

[Christopher R. Rice]

Originally Posted by Varyon

Heavy Plate isn't a +0.5 CF, and for good reason. Otherwise, you'd be looking at $600 off for being cheap for all thicknesses of plate armor - but with scale armor, for example, it varies depending on what thickness (because it doesn't follow the heavy plate rules). Honestly, I'd say the issue here is less with the heavy plate rules and more with Cheap being a static -1 DR but a price multiplier (a below-1 multiplier, but a multiplier nonetheless). Cheap being the same level of protection but with a weight multiplier would make that issue go away. Off the top of my head, something like -60% cost (as it is now) and +50% weight might work - that matches with how DR 3 plate works currently.

Hmmmm. Not bad. Not bad at all.

[Anthony]

Originally Posted by Varyon

Heavy Plate isn't a +0.5 CF, and for good reason. Otherwise, you'd be looking at $600 off for being cheap for all thicknesses of plate armor - but with scale armor, for example, it varies depending on what thickness (because it doesn't follow the heavy plate rules). Honestly, I'd say the issue here is less with the heavy plate rules and more with Cheap being a static -1 DR but a price multiplier

Well, they're actually both aspects of the same problem, because the heavy plate rules actually only work properly when applied to cheap armor. DR 6 should be twice the weight of DR 3, but for 'standard' quality armor it's actually 2.5x heavier. For cheap armor, it's actually the correct ratio.

[Varyon]

Let me preface this by saying to King Leonidas that what you're seeing here is basically just a group of gearheads debating minutiae, and you can safely disregard it if it doesn't interest you.

Originally Posted by Anthony

Well, they're actually both aspects of the same problem, because the heavy plate rules actually only work properly when applied to cheap armor. DR 6 should be twice the weight of DR 3, but for 'standard' quality armor it's actually 2.5x heavier. For cheap armor, it's actually the correct ratio.

I recall Dan giving a feasible rationale behind the heavy plate progression (and disagreeing with the purely-linear progression seen in the Pyramid armor design system), but I can't find it now. Personally, I favor using the Pyramid version, as that gives you a lot more room to tweak things, regardless of if it's more or less accurate than the heavy plate progression. But even if the heavy plate rules were purely linear, being $333.33 and 8/3 lb per DR for torso armor, you'd still have the issue of Cheap becoming a better deal the higher the DR. In that case, you'd be looking at $1,000 and 8 lb for DR 3 plate or $533.33 and 10.67 lb for DR 3 cheap plate, saving $466.67 in exchange for being 2.67 lb heavier. Meanwhile, DR 9 plate would be $3,000 and 24 lb, while DR 9 cheap plate would be $1,333.33 and 26.67 lb, saving $1666.67 in exchange for being 2.67 lb heavier. Cheap really needs to either be a percent reduction in DR or, more feasibly (so you don't have to deal with fractional DR and the rounding issues that would introduce), a percent increase in weight.

[Rupert]

Originally Posted by Varyon

I recall Dan giving a feasible rationale behind the heavy plate progression (and disagreeing with the purely-linear progression seen in the Pyramid armor design system), but I can't find it now.

I assume that the assumption is that angling, surface treatments, interior padding, and so on give you +1 DR 'for free'.

[Pursuivant]

Originally Posted by King Leonidas

is this RAW?

Good God, no! Just ideas on how a GM can screw with players who buy or make cheap armor if someone wants the extra detail.

Armor failure can also explain certain critical hits, if a GM wants dramatic narration beyond than "critical hit to the head, roll damage."

[Anthony]

Originally Posted by Varyon

I recall Dan giving a feasible rationale behind the heavy plate progression.

I recall him giving a rationale but I wouldn't call it feasible.

[DanHoward]

The amount of energy required to penetrate steel plate doesn't increase linearly with thickness.

According to Williams (p.929-929):

The amount of energy for a bullet to penetrate 1mm of mild steel is E.
The amount of energy to penetrate 2mm = E x 3
The amount of energy to penetrate 3mm = E x 5.8
The amount of energy to penetrate 4mm = E x 9.2

[Anthony]

Originally Posted by DanHoward

The amount of energy required to penetrate steel plate doesn't increase linearly with thickness.

No-one said it did, but GURPS damage isn't linear in energy either.

Originally Posted by DanHoward

The amount of energy for a bullet to penetrate 1mm of mild steel is E.
The amount of energy to penetrate 2mm = E x 3
The amount of energy to penetrate 3mm = E x 5.8
The amount of energy to penetrate 4mm = E x 9.2

That ratio actually varies with the bullet, but is significantly beyond the amount of modeling GURPS is interested in doing. To the degree GURPS damage is handled consistently at all (melee weapon damage is pretty much nonsense) it's measured in RHA equivalent, which means DR is just thickness * quality factor.