Would it be possible to have a reaction create a new creature? I'm considering modding in a race of stone people who can't breed, but can replenish their ranks by carving new people from solid rock, and I'm curious as to if this is workable.
Without DFHack it takes a bit more work, but you can still create a creature. You can do this by creating a material that carries a syndrome that will temporarily turn the person running the reaction into another creature. This new creature will have a body part that is designed to fall off immediately, and then the person will turn back to normal. Give your race an interaction that can resurrect the body part and have it transform into your race.
It is important that the interaction resurrects and not animates, as animation creates zombies. It is also important to make sure that only the special creature used to create the body part can be affected by the interaction, otherwise everything that dies can become brought back to life and turned into a stone person.
Problem with this body parts that are animated/resurrected and transformed are considered "civless" friendly creatures, his best bet would be to have a special pet like this:
[CREATURE:ESSENCE_SPAWNER]
[NAME:essence beetle:essence beetles:essence]
[CREATURE_TILE:10][COLOR:7:0:1]
[BENIGN]
[CANOPENDOORS]
[PREFSTRING:masterful design]
Now we'll declare the specific castes.
[CASTE:FEMALE_BEETLE]
[POP_RATIO:1] --- Either buy or have a mirgrant wave bring one
[FEMALE][PETVALUE:99][COMMON_DOMESTIC][PET][SPEED:850]
[LITTERSIZE:1:1] --- can only make 1 essence at a time.
[CASTE_NAME:essence beetle:essence beetles:essence][CASTE_TILE:'b'][CASTE_COLOR:7:2:1]
[BODY:INSECT:2EYES:2LUNGS:HEART:GUTS:ORGANS:BRAIN:MOUTH]
[BODY_DETAIL_PLAN:CHITIN_MATERIALS]
[BODY_DETAIL_PLAN:CHITIN_TISSUES]
[BODY_DETAIL_PLAN:EXOSKELETON_TISSUE_LAYERS:CHITIN:FAT:MUSCLE]
[SELECT_TISSUE_LAYER:HEART:BY_CATEGORY:HEART]
[TL_MAJOR_ARTERIES]
[BODY_DETAIL_PLAN:STANDARD_HEAD_POSITIONS]
[USE_MATERIAL_TEMPLATE:SINEW:SINEW_TEMPLATE]
[TENDONS:LOCAL_CREATURE_MAT:SINEW:200]
[LIGAMENTS:LOCAL_CREATURE_MAT:SINEW:200]
[HAS_NERVES][GRAZER:1000][GOBBLE_VERMIN_CLASS:EDIBLE_GROUND_BUG]
[ATTACK:BITE:BODYPART:BY_CATEGORY:MOUTH]
[ATTACK_SKILL:BITE]
[ATTACK_VERB:bite:bites]
[ATTACK_CONTACT_PERC:100]
[ATTACK_PENETRATION_PERC:100]
[ATTACK_FLAG_EDGE]
[ATTACK_PRIORITY:MAIN]
[ATTACK_FLAG_CANLATCH]
[DESCRIPTION:(SIZE=6)(BASE=Beetle)(FOOD=Grass/Moss) A small modified beetle designed by shapers for the creation of essence, a servant mind however is required to activate production. Essence beetles have the same micro organisms that are in essence pools, they responsible for the conversion of sunlight and organic matter into essence. Since the beetle cannot absorb sunlight, magic is directed from a servant mind to activate the mirco organisms.]
[CREATURE_CLASS:BREEDER] --- Classes it as a breeder, used for interaction disrinction
[NOPAIN][EXTRAVISION][NOSTUN][NOEMOTION][NOFEAR]
[LARGE_ROAMING][NOBONES]
[USE_MATERIAL_TEMPLATE:ICHOR:ICHOR_TEMPLATE]
[BLOOD:LOCAL_CREATURE_MAT:ICHOR:LIQUID]
[BODY_SIZE:0:0:6000]
[ROOT_AROUND:BY_TOKEN:RF1:root around in:roots around in]
[ROOT_AROUND:BY_TOKEN:LF1:root around in:roots around in]
[SET_TL_GROUP:BY_CATEGORY:ALL:CHITIN]
[TL_COLOR_MODIFIER:GRAY:1]
[TLCM_NOUN:chitin:SINGULAR]
[SET_TL_GROUP:BY_CATEGORY:EYE:EYE]
[TL_COLOR_MODIFIER:BLACK:1]
[TLCM_NOUN:eyes:SINGULAR]
[CASTE:MALE_MIND]
[POP_RATIO:1][INTELLIGENT][NO_DRINK][NO_SLEEP][NO_EAT]
[MALE][PETVALUE:599][COMMON_DOMESTIC][PET] --- Is needed for essence pools to work
[CASTE_NAME:servant mind:servant minds:servant mind]
[CASTE_TILE:15]
[BODY:QUADRUPED:TAIL:2EYES:2EARS:NOSE:2LUNGS:HEART:GUTS:ORGANS:THROAT:SPINE:BRAIN:SKULL:MOUTH:TONGUE:FACIAL_FEATURES:TEETH:RIBCAGE]
[DESCRIPTION:(SIZE=50) A servant mind is the only creation that Shapers have given a high level of intelligence to, they can also hold and direct magical and normal energy to various machines and shaper projects.]
[CREATURE_CLASS:CONTROL] --- Classes it as a controller, used for interaction disrinction
[USE_MATERIAL_TEMPLATE:SINEW:SINEW_TEMPLATE]
[TENDONS:LOCAL_CREATURE_MAT:SINEW:200]
[LIGAMENTS:LOCAL_CREATURE_MAT:SINEW:200]
[HAS_NERVES]
[BODY_DETAIL_PLAN:STANDARD_MATERIALS]
[BODY_DETAIL_PLAN:STANDARD_TISSUES]
[USE_MATERIAL_TEMPLATE:BLOOD:BLOOD_TEMPLATE]
[STATE_COLOR:ALL:GREEN]
[BLOOD:LOCAL_CREATURE_MAT:BLOOD:LIQUID]
[CREATURE_CLASS:GENERAL_POISON]
[GETS_WOUND_INFECTIONS]
[GETS_INFECTIONS_FROM_ROT]
[USE_MATERIAL_TEMPLATE:PUS:PUS_TEMPLATE]
[PUS:LOCAL_CREATURE_MAT:PUS:LIQUID]
[BODY_DETAIL_PLAN:VERTEBRATE_TISSUE_LAYERS:SKIN:FAT:MUSCLE:BONE:CARTILAGE]
[BODY_DETAIL_PLAN:STANDARD_HEAD_POSITIONS]
[BODY_DETAIL_PLAN:HUMANOID_HEAD_POSITIONS]
[BODY_DETAIL_PLAN:HUMANOID_RIBCAGE_POSITIONS]
[SET_TL_GROUP:BY_CATEGORY:ALL:SKIN]
[TL_COLOR_MODIFIER:COPPER:1:PALE_BROWN:1:PALE_CHESTNUT:1:PALE_PINK:1:PEACH:1:PINK:1:TAN:1:TAUPE_PALE:1:TAUPE_SANDY:1]
[TLCM_NOUN:skin:SINGULAR]
[TISSUE_LAYER_APPEARANCE_MODIFIER:WRINKLY:0:0:0:0:0:0:0]
[APP_MOD_RATE:1:YEARLY:0:100:30:0:NO_END]
[APP_MOD_NOUN:skin:SINGULAR]
[APP_MOD_DESC_RANGE:0:0:0:1:25:50]
[CAN_DO_INTERACTION:MAGIC_MISSLE]
[CDI:ADV_NAME:Cast searer]
[CDI:USAGE_HINT:ATTACK]
[CDI:BP_REQUIRED:BY_CATEGORY:MOUTH]
[CDI:FLOW:FIREBALL]
[CDI:VERB:cast searer:casts searer:NA]
[CDI:TARGET:C:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:C:15]
[CDI:MAX_TARGET_NUMBER:C:1]
[CDI:WAIT_PERIOD:300]
[CDI:FREE_ACTION]
[CAN_DO_INTERACTION:MAGIC_MISSLE_4]
[CDI:ADV_NAME:Cast ice shards]
[CDI:USAGE_HINT:ATTACK]
[CDI:BP_REQUIRED:BY_CATEGORY:MOUTH]
[CDI:MATERIAL:WATER:SOLID_GLOB]
[CDI:VERB:cast ice shards:casts ice shards:NA]
[CDI:TARGET:C:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:C:15]
[CDI:MAX_TARGET_NUMBER:C:1]
[CDI:WAIT_PERIOD:30]
[CDI:FREE_ACTION]
[CAN_DO_INTERACTION:SLOW]
[CDI:ADV_NAME:Cast slow]
[CDI:BP_REQUIRED:BY_CATEGORY:MOUTH]
[CDI:VERB:cast slow:casts slow]
[CDI:USAGE_HINT:ATTACK]
[CDI:TARGET_RANGE:A:15]
[CDI:TARGET:A:LINE_OF_SIGHT]
[CDI:MAX_TARGET_NUMBER:A:1]
[CDI:WAIT_PERIOD:300]
[CDI:FREE_ACTION]
[CAN_DO_INTERACTION:BEFUDDLE]
[CDI:ADV_NAME:Cast befuddle]
[CDI:BP_REQUIRED:BY_CATEGORY:MOUTH]
[CDI:VERB:cast befuddle:casts befuddle]
[CDI:USAGE_HINT:ATTACK]
[CDI:TARGET_RANGE:A:15]
[CDI:TARGET:A:LINE_OF_SIGHT]
[CDI:MAX_TARGET_NUMBER:A:1]
[CDI:WAIT_PERIOD:300]
[CDI:FREE_ACTION]
[BODY_SIZE:0:0:50000]
[CASTE:ESSENCE] --- used to make creations
[POP_RATIO:225000][CASTE_COLOR:2:0:1]
[CAN_LEARN][NO_EAT][NO_DRINK][NO_SLEEP]
[CASTE_NAME:essence:essence:essence]
[CASTE_TILE:7]
[BODY:BASIC_1PARTBODY_THOUGHT] - probally 1 part body with thought
[DESCRIPTION:(SIZE=3) raw essence, ready to be used.]
[TISSUE:MATTER]
[TISSUE_NAME:plant matter:plant matter]
[TISSUE_MATERIAL:INORGANIC:STONE]
[MUSCULAR]
[FUNCTIONAL]
[STRUCTURAL]
[RELATIVE_THICKNESS:1]
[CONNECTS]
[TISSUE_SHAPE:LAYER]
[TISSUE_LAYER:BY_CATEGORY:ALL:MATTER]
[CREATURE_CLASS:ESSENCE]
[NOT_LIVING][NOBONES][NOBREATHE][NOSTUN][NONAUSEA][NO_DIZZINESS][NO_FEVERS][NOPAIN][NOFEAR]
[BODY_SIZE:0:0:3000][IMMOBILE]
[CASTE_PROFESSION_NAME:CHILD:(fresh):(fresh)]
end-of-castes
[SELECT_CASTE:ALL] --- now adding everything
general-tag-assignment
[CHILD:1]
[GENERAL_BABY_NAME:fresh essence:fresh essence]
[BABYNAME:fresh essence:fresh essence] --- that's fresh
[NOEMOTION][NOEXERT][NOT_BUTCHERABLE]
[DIURNAL]
[SWIMS_INNATE][SWIM_SPEED:2500]
[HOMEOTHERM:10050]
Creature can be bought (male and female) but their castes are so rare they never show in fortress mode, however their offspring are not PET and are INTELLIGENT, thus when the child is transformed to your race it gains sentience in a sense (since the pet IS a part of your civ) side effects are:
-Only origional controlled race can fill noble roles (commanders of squads, brooker, etc)
-They must do something noteable to make them historical if you want them to join the army (sometimes if you wait long enough they show up for recruitment, but making a masterwork item is the fastest way)
-They will have no name (only profession gives them away) and have a <tame> attached to them forever