Basically what the idea is, was to make a heavier version of the scatterlight suit. Like take a suit of heavy armor (full plate lets say), and craft on the technical function of the scatterlight onto the armor. Figuring I'd need the craft feat for tech arms and armor. But what would I do about the cost? In some other threads I've seen people mention RAW that if you had 2 different armors worn, you take the best armor bonus, but the worst max dex, ACP, etc. Anyone know where this is written?
The rule is that no-one can wear two suits of armor. Plate armor won't fit over a breastplate, and while it will fit over a gambeson (padded armor) we can assume that plate armor already has a gambeson as part of it.
However, there are exceptions and my NPC gunslinging bloodrager Val Baine uses one of them. (I had aged Val from Fires of Creation to 17 years old to accommodate a Local Ties trait, and my mischievous players threw me the plot twist of inviting her into the party.) Those exceptions are the Armored Kilt and the Armored Coat.
Armored Coat
Medium Armor, Cost 50 gp, Armor Bonus +4, Max Dex Bonus +3, Armor Check Penalty -2, Arcane Spell Failure Chance 20%, Speed reduced by 10 ft., Weight 20 lbs., Source Advanced Player’s Guide.This sturdy leather coat is reinforced with metal plates sewn into the lining. More cumbersome than light armor but less effective than most medium armors, the advantage of an armored coat is that a person can don it or remove it as a move action (there is no "don hastily" option for an armored coat). If worn over other armor, use the better AC bonus and worse value in all other categories; an armored coat has no effect if worn with heavy armor. The only magic effects that apply are those worn on top.
Val donned a red-ranked scattersuit and then wore an armored coat over it. I styled the coat to look like a Western longcoat, which fit her gunslinger motif, though real armored coats look more like a short metal jacket. It started a fashion trend--the gunslinger took to wearing an armored coat, too.
The scatterlight suit says, "This bonus to touch AC only applies to attacks made by beam weapons and rays—-it does not provide additional protection to other touch attacks," but the rules do not define beam weapons. Posting in the Rules Forum, What is a Beam Weapon?, did not give a definite answer. So I decided that a beam weapon was any ranged weapon that dealt a touch attack and did not shoot a projectile. A weapon that shot a stream of nanites counted as a beam weapon.
Later Val made an mithral armored coat to reduce the weight and remove the speed penalty: that was another GM call to decide whether the armored coat had enough metal in it to benefit from mithral. She upgraded to a blue-ranked scatterlight suit and then abandoned scatterlight suits entirely to wear a Robe of Arcane Heritage (houseruled to work on bloodragers). People and robots were not shooting enough beam weapons at her to justify the scatterlight suit.
As far as I know that would be GM call.
If tech weapons hitting you is a problem there is an easier solution. Resist energy. Get Lesser Extend rod and it will last 20 min/ level. Robots use mainly lasers so resist fire. We have encountered a few sonic weapon users, a few zero weapon users and a few plasma users. My experience is to always have resist fire up. On every one. Resist electricity is a good secondary and have someone keep one communal resistance ready for when you meet sonic or zero weapon users. Also protection from energy against bosses like Hellion whose damage might exceed your current energy resistance.
Two of our characters were recently engulfed by a plasma ooze dealing 4d6 fire, 4d6 electricity and some bludgeoning damage. With resist fire and electricity 30 up we took no elemental damage whatsoever. Without them we would have been toast, literally.
Won't help you against bullets but those have been quite rare for some reason. Protection from arrows helps a little against bullets and certain monsters flinging around poisonous spikes.
Another approach is miss chance. Wind walls, Fickle winds, Mirror Images, Fog clouds. Later on almost everything will see through your Mirror images though but for now it should help.
Cheap neck slot item Stormlure gives 50% miss chance against ranged attacks for one minute, enough for the boss battle or against those thankfully rare chaingun wielding robots.
By the way, for creating new kinds of technological items, Lord Fyre and I figured out the rules for the cost of technological items in [Technology] The Wires Behind the Magic.
Val Baine learned Bullet Shield when she stopped using the scatterlight suit. However, WagnerSika's suggestion, Resist Energy, is better because the stronger robot with a plasma weapon, the Annihilator Robot, uses it as an area of effect.