Object materials

Object materials is the name of a system that allows various objects to generate made of something different from their ordinary base material. It was first introduced in NetHack brass, and L later made it into a standalone patch that can be found here.

Variants that incorporate some kind of object materials include GruntHack, dNetHack, xNetHack, SpliceHack, and EvilHack; GruntHack's implementation is much different from that of L's patch, and thus different from other variant implementations.

A user has suggested improving this page or section as follows:

"All the variants that implement object materials do them slightly differently, and should be noted - per the above, only GruntHack is listed currently. Also, add a section describing what unusual properties might come from different-material objects. For example, flesh objects can be eaten."

Monsters

In games with some form of object materials included (typically variants), monsters also have various interactions with each type of object.

Material hatred

Material hatred is used to refer to any particular material that deals extra damage to a certain type of monster, much like the vanilla interactions between werecreatures and silver. For example, elves may have an aversion to iron weapons, and leprechauns may be able to steal anything made of gold.

Golems

Golems that are generated randomly or via polypiling in games with object materials will death drop items made of that material in addition to the standard "corpse" of objects they leave behind.

Leprechauns

Leprechauns in games with object materials are usually given the ability to steal items made of gold as well as zorkmids.

Croesus

Many variants with object materials give Croesus golden weapons and/or armor.

GruntHack

Item generation

Base objects	Converts to	Probability (%)
Iron non-dwarvish weapons, weapon-tools, and armor	Iron	80
	Wood	5
	Silver	5
	Copper	3
	Mithril	3
	Gold	1
	Bone	1
	Glass	1
	Plastic	1
Wooden non-elven non-dwarvish weapons, weapon-tools, armor, chests, and large boxes	Wood	80
	Stone	10
	Iron	5
	Bone	3
	Copper	1
	Silver	1
Cloth or leather armor	Cloth	60
	Leather	33
	Paper	6
	Flesh	1
Dwarvish armor: dwarvish helms, chain mails, cloaks, and roundshields; and weapons: dwarvish spears, short swords, and mattocks	Iron	85
	Mithril	10
	Copper	2
	Silver	1
	Gold	1
	Platinum	1
Elven weapons and elven shields	Wood	80
	Copper	10
	Mithril	5
	Silver	3
	Gold	2
Elven chain mails and helms	Copper	80
	Mithril	20

Weights of different materials

When calculating an object's base weight, its weight is multiplied by a factor of current material multiplier / base object material multiplier, where the multipliers are:

Material	Multiplier
Liquid	1
Wax	1
Veggy	1
Flesh	1
Paper	1
Cloth	2
Leather	3
Wood	4
Bone	5
Dragonhide	2
Iron	12
Metal	12
Copper	10
Silver	12
Gold	14
Platinum	10
Mithril	6
Plastic	3
Glass	5
Gemstone	16
Mineral	14

Effect on AC

When calculating a piece of armor's total AC, a material bonus is calculated, which is usually current material AC - base armor material AC. If this material bonus is negative, it will decrease the base AC of the armor, to a minimum of 0. Thus, higher material AC is better. The material AC values are:

Material	Material AC
Liquid	-5
Wax	-4
Veggy	-4
Flesh	-2
Paper	-4
Cloth	-3
Leather	-2
Wood	-1
Bone	+1
Dragonhide	+5
Iron	0
Metal	0
Copper	-1
Silver	0
Gold	-2
Platinum	-1
Mithril	0
Plastic	-2
Glass	0
Gemstone	+2
Mineral	+3

Cost

When calculating the base cost of an object, the cost is multiplied by a factor of current material cost multiplier / base object material cost multiplier. The multipliers are:

Material	Multiplier
Liquid	1
Wax	1
Veggy	1
Flesh	3
Paper	2
Cloth	3
Leather	5
Wood	8
Bone	20
Dragonhide	200
Iron	10
Metal	10
Copper	10
Silver	30
Gold	30
Platinum	30
Mithril	32
Plastic	10
Glass	20
Gemstone	500
Mineral	10