How to make all generated leather/bone a generic one instead of "species_name" leather/bone? (I failed to find separate bone/leather definitions in raws, only "template"s...)
(Can it be done easily? Some mods advertise this...)
Does it really improve perfomance?
...
I don't know about performance improvements, but this is how generic leather is implemented in the Fallout Equestria RAWs...
In the skin material definition (in material_template_default), replace this...
[MATERIAL_REACTION_PRODUCT:TAN_MAT:LOCAL_CREATURE_MAT:LEATHER]
[MATERIAL_REACTION_PRODUCT:PARCHMENT_MAT:LOCAL_CREATURE_MAT:PARCHMENT]
...with this...
[MATERIAL_REACTION_PRODUCT:TAN_MAT:CREATURE_MAT:ANIMAL:LEATHER]
[MATERIAL_REACTION_PRODUCT:PARCHMENT_MAT:CREATURE_MAT:ANIMAL:PARCHMENT]
...and stick this in one of the creature files somewhere...
[CREATURE:ANIMAL]
[NAME:::]
[ARENA_RESTRICTED]
[DOES_NOT_EXIST]
[USE_MATERIAL_TEMPLATE:LEATHER:LEATHER_TEMPLATE]
[USE_MATERIAL_TEMPLATE:PARCHMENT:PARCHMENT_TEMPLATE]
I believe that is everything you need. I *think* this should also work for bones and other things that aren't processed but used directly off the creature, but you would have to replace [TISSUE_MAT:LOCAL_CREATURE_MAT:BONE] with [TISSUE_MAT:CREATURE_MAT:ANIMAL:BONE] in the tissue template definition for bones instead of changing material templates, in addition to adding [USE_MATERIAL_TEMPLATE:BONE:BONE_TEMPLATE] to ANIMAL. If that works, you could also swap out the skin material reactions for just making skin generic.
How to make all metal items to return 100% of material used in their construction when melting?
Melting is hard coded. Short of making custom melting reactions or doing some weird script based hackery, you can't do this afaik.
Does it really impact perfomance if one permits all metal items to be made from all metals/alloys?
(That one I did, but the change corresponded with mass turkey hatchings in my fortress, so was hard to tell.)
I have literally never heard anything about this before, so no clue.