Engineering guide
This guide explains what the Engineering skill and every Engineering perk really do in game v1.5.7: how siege engines are built faster, hit more often, hit harder, reload faster and last longer, what the governor halves do for your towns and castles, what the battle halves give you and your troops, and which perks behave differently from their tooltips. The siege numbers (bombardment, engine construction, engine hit points, walls, crew casualties, prebuilt engines) belong to the base game; SandBox provides the player's siege production menu, where the fire engines are offered. The battle halves (shield hit points, ammo, armor, damage) are SandBox's models. NavalDLC extends the agent damage, agent stats, army management and building construction models; its prosperity, clan finance and battle reward models pass the Engineering effects through unchanged. On a ship with upgrades the Scaffolds (secondary) and Military Planner (primary) bonuses are lost in the first shield or ammo slot. NavalDLC adds a policy term to the building construction model and a Nord culture feat to the army management model. StoryMode extends and replaces parts of the battle reward models in the story campaign.
For exact formulas, edge cases and links to the game code, see the deep dives: Sieges (hit chance, damage, rate of fire, construction progress, engine and wall hit points, prebuilt and fire engines, crew casualties), Settlements (construction power, boosts, prosperity, project income, food stock, recruit slots), Combat agent stats (shield hit points, siege ammo, armor), Combat damage (crossbow, shield and melee damage), Battles (troop experience when an engine is built, loot modifiers), Party and map (army cohesion) and Characters and politics (prisoner escape).
Who holds the perk. Each half is read from one hero, and the role decides who:
- Engineer: the hero in the Engineer role of a party. For siege numbers it is the engineer of the side's effective siege party, the party the siege treats as that side's lead. Most siege halves read the engineer of the side's effective siege party. The exceptions: Military Planner reads your own party's engineer, Masterwork reads the party leader, the fire engines read the player's party, Engineering Guilds reads the recruiting hero's party, and Metallurgy reads the looting party.
- Governor: the governor of the town or castle. Some governor halves need the governor to be in the settlement; each one below says whether it does.
- Captain: the hero leading a formation in battle. The bonus goes to the troops of that formation, not to the captain himself.
- Army commander: the leader of the army.
- Personal: the hero's own character.
What the verdicts mean.
works: does what the tooltip says, or more; broader effects are noted.differs: narrower, different or extra conditions or values compared with the tooltip.unused: never read by the game.ui_only: only shown in the interface.
The tooltip also shows each half's environment line. "Reduced effect at sea" is shown on the secondaries of Scaffolds and Torsion Engines. "Land only" is shown on the primaries of Torsion Engines, Dungeon Architect, Carpenters, Military Planner, Wall Breaker, Foreman, Salvager, Battlements, Camp Building, Apprenticeship, Improved Tools, Architectural Commissions, Clockwork and Masterwork, and on the secondaries of Dreadful Besieger, Wall Breaker, Siege Engineer, Stonecutters, Camp Building, Improved Tools and Metallurgy. Because the tooltip says so, the environment is not a reason for differs below. Halves not listed have no environment line.
No Engineering perk is unused or ui_only. One reader of the Faster building production skill effect only builds its tooltip text (ui_only); the effect itself works.
What unlocks what
Every 25 points of Engineering opens a new pair. You pick one perk of each pair; the other is locked for that hero. Engineering 275 has a single perk.
| Engineering | Perk A | Perk B |
|---|---|---|
| 25 | Scaffolds: +10% build speed for rams and siege towers; +30% shield hit points | Torsion Engines: +10% build speed for ranged siege engines; +3 crossbow bolt damage |
| 50 | Dungeon Architect: −25% chance that defenders hit your ranged engines; −25% hero prisoner escape | Siegeworks: +10% hit points for ranged engines; +1 prebuilt catapult as governor |
| 75 | Carpenters: +33% hit points for rams and siege towers; +12% town construction | Military Planner: +50% ammo when assaulting a siege; +25% castle construction |
| 100 | Dreadful Besieger: +10% accuracy for the governed settlement's engines; +5% crossbow damage for your formation | Wall Breaker: +25% bombardment damage to walls; +10% shield damage for your formation |
| 125 | Foreman: +10% mangonel and trebuchet accuracy; +100 prosperity per finished project | Salvager: +20% ballista accuracy; +0.1% defender engine build speed per militia |
| 150 | Siege Engineer: +30% hit points for defender engines; fire engines | Stonecutters: +30% construction for fortifications and barracks; fire engines |
| 175 | Battlements: +1 prebuilt ballista in your siege camp; +100 food stock | Camp Building: −50% army cohesion loss while besieging; −20% crew casualty chance |
| 200 | Apprenticeship: +5 experience per troop when an engine is built; +1% prosperity gain per building | Engineering Guilds: +1 recruit slot at artisans; +25% wall hit points |
| 225 | Improved Tools: +20% build speed before the camp is built; +5% melee damage for your formation | Metallurgy: 30% chance to clean negative modifiers off loot; +5 armor for your formation |
| 250 | Architectural Commissions: +25% mangonel and trebuchet rate of fire; +20 gold a day from daily projects | Clockwork: +25% ballista rate of fire; +20% project boosts in the governed town |
| 275 | Masterwork: +1% bombardment damage per Engineering point above 250 (no alternative) | — |
How the siege numbers combine
Every siege number below (hit chance, damage, rate of fire, construction progress, engine hit points) adds its percentages together and applies them once:
Siege number = engine's base value × (1 + sum of all percentage bonuses that apply)
- Engine's base value: each engine type has its own hit chance, damage, hit points, rate of fire per day and man-day cost in the game data.
- Percentage bonuses: the Engineering skill effect and every perk whose conditions hold for that engine and side. They are added, not multiplied with each other.
Two exceptions: when the besiegers fire at the defenders' ranged engines, the wall level first takes 0.05 / 0.1 / 0.15 (wall level 1 / 2 / 3) off the hit chance before the percentages, and a hit chance below 0 counts as 0. Ranged engines are the ballista, fire ballista, mangonel (onager), fire mangonel, trebuchet, catapult and fire catapult; the non-ranged engines are rams and siege towers.
Tier 1 (Engineering 25): Scaffolds or Torsion Engines
Scaffolds
- Primary, +10% build speed for non-ranged siege engines (engineer;
works). Rams and siege towers of your side are built 10% faster. It is skipped while the siege camp is not yet built and the same engineer holds Improved Tools, because Improved Tools takes its place then. Without Improved Tools it also applies before the camp is built. - Secondary, +30% shield hit points (personal;
differs). Every shield you carry into battle starts with 30% more hit points. In a naval battle on a ship with upgrades, the first shield slot is reset after deployment and loses this bonus.
Torsion Engines
- Primary, +10% build speed for ranged siege engines (engineer;
works). Same rules as Scaffolds, for ranged engines. - Secondary, +3 damage with crossbows (personal;
works). A crossbow bolt that hits a body bone of the target does 3 more damage.
Worked example. The besiegers have 400 healthy men (a man-day power of 20) and build a ranged engine with a man-day cost of 10 (an example value) after the camp is built. Their engineer has Engineering 150 and Torsion Engines:
A besieger side with 400 healthy men (available man-day power 20) builds a ranged engine with a man-day cost of 10 (an example value) after the siege camp is built; its engineer has Engineering 150 and Torsion Engines. Inputs: available man day power 20, man day cost 10.
| Step | Source | Stage | Change | Running value |
|---|---|---|---|---|
| Base | Siege engine construction progress per hour | base | 0.0833 | |
| 1 | Torsion Engines | factor +10% | +0.0084 | 0.0917 |
| 2 | Faster siege engine production | factor +15% | +0.0125 | 0.1042 |
| Result | Siege engine construction progress per hour | 0.1042 |
With these inputs, siege engine construction progress per hour is 0.1042.
The skill effect adds +15% and Torsion Engines +10%, so the engine gains 0.1042 of its build per hour instead of 0.0833.
Which one? Scaffolds speeds up rams and siege towers and adds 30% to your shields' hit points; Torsion Engines speeds up ranged engines and adds crossbow damage.
Tier 2 (Engineering 50): Dungeon Architect or Siegeworks
Dungeon Architect
- Primary, −25% chance that your ranged engines get hit (engineer;
differs). It only protects the besiegers' ranged engines: when the defenders fire at the besiegers' ranged engines and the besiegers' engineer holds the perk, each shot has a 25% lower hit chance. A defending holder's engines get nothing. - Secondary, −25% prisoner escape chance (governor;
differs). Only hero prisoners (not the main hero) held in the town or castle you govern are affected; their daily escape chance (base 0.04, before other modifiers) drops by 25%. Regular troop prisoners are not affected. The governor has to be in the settlement.
Siegeworks
- Primary, +10% hit points for ranged siege engines (engineer;
works). Ranged engines of the engineer's side have 10% more hit points, whether that side is besieging or defending. - Secondary, +1 prebuilt catapult when a siege starts (governor;
differs). When a siege starts at the town or castle you govern, the defenders get one more catapult already built. The count is a fixed one, not read from the perk's value, so the result matches the tooltip. The governor does not need to be in the settlement.
Which one? Dungeon Architect protects a besieging side's ranged engines and makes hero prisoners in your dungeon 25% less likely to escape; Siegeworks adds 10% hit points to ranged engines on either side and gives a governed fortification an extra catapult.
Tier 3 (Engineering 75): Carpenters or Military Planner
Carpenters
- Primary, +33% hit points for rams and siege towers (engineer;
works). Only the besiegers' rams and siege towers. - Secondary, +12% construction speed in the governed town (governor;
works). Projects in the town you govern are built 12% faster. Towns only; the governor has to be in the town and a project has to be in progress.
Military Planner
- Primary, +50% ammunition when besieging (engineer;
works). In a siege assault where your party attacks, every arrow, bolt and throwing-weapon stack of your party's troops holds 50% more. Only your own party's engineer counts, not the army's or another party's. It does not apply to sally-out battles or battles outside the walls. Land only, as the tooltip shows. - Secondary, +25% construction speed in the governed castle (governor;
works). Castles only; the governor has to be in the castle and a project has to be in progress.
Worked example. A castle with prosperity 2000 and no construction buildings; its governor has Engineering 200 and Military Planner and stays in the castle:
A castle with prosperity 2000 and no construction buildings; its governor has Engineering 200 and Military Planner and stays in the castle while a project is in progress. Inputs: prosperity 2000.
| Step | Source | Stage | Change | Running value |
|---|---|---|---|---|
| Base | Daily construction power of a town or castle | base | 20.0000 | |
| 1 | Military Planner | factor +25% | +5.0000 | 25.0000 |
| 2 | Faster building production | factor +50% | +10.0000 | 35.0000 |
| Result | Daily construction power of a town or castle | 35.0000 |
With these inputs, daily construction power of a town or castle is 35.0000.
The castle starts at 1% of its prosperity, 20.0000 a day. The skill effect adds +50% and Military Planner +25%, so it builds 35.0000 a day.
Which one? Carpenters protects your rams and siege towers and speeds up construction in a governed town; Military Planner gives your troops more ammo in siege assaults and speeds up construction in a governed castle.
Tier 4 (Engineering 100): Dreadful Besieger or Wall Breaker
Dreadful Besieger
- Primary, +10% accuracy for the governed settlement's siege engines (governor;
differs). Only the defenders' shots at the besiegers' ranged engines get +10% hit chance; shots at the besieging troops get nothing. The governor does not need to be in the settlement. - Secondary, +5% crossbow damage by troops in your formation (captain;
works). A crossbow bolt from a troop of the captain's formation that hits a body bone does 5% more damage. The captain's own hits do not count.
Wall Breaker
- Primary, +25% bombardment damage to walls (engineer;
works). Besieger shots at the walls do 25% more damage. - Secondary, +10% damage to shields by troops in your formation (captain;
works). Hits by the captain's formation that are blocked with a shield do 10% more damage to that shield, with any weapon. A hit on a shield carried on the back also gets the +10%, and there it raises the damage to the troop itself. The captain's own hits do not count.
Which one? Dreadful Besieger helps a governed settlement's engines against the besiegers' engines and the crossbowmen of a captain's formation; Wall Breaker helps besiegers bring down walls and helps a formation break shields.
Tier 5 (Engineering 125): Foreman or Salvager
Foreman
- Primary, +10% mangonel and trebuchet accuracy (engineer;
works). Mangonels, fire mangonels and trebuchets of the engineer's side get +10% hit chance, at any target and on either side. - Secondary, +100 prosperity when a project is finished (governor;
works). Each time a building in the governed settlement gains a level, the settlement gets +100 prosperity. The governor does not need to be in the settlement.
Salvager
- Primary, +20% ballista accuracy (engineer;
works). Ballistas and fire ballistas of the engineer's side get +20% hit chance, at any target and on either side. - Secondary, +0.1% siege engine build speed per militia (governor;
works). When the town or castle you govern is besieged, its engines are built 0.1% faster for every militia man. The governor has to hold the perk and be in the settlement.
Salvager bonus = 0.1% × the settlement's militia
- Militia: the besieged settlement's current militia.
Worked example. A besieged town with 300 militia and 400 healthy defenders (a man-day power of 20) builds an engine with a man-day cost of 10 (an example value). The defenders' engineer has Engineering 100; the governor has Salvager and is in the town:
A besieged town with 300 militia and 400 healthy defenders (available man-day power 20) builds an engine with a man-day cost of 10 (an example value); the defenders' engineer has Engineering 100, and the governor has Salvager and is in the town. Inputs: available man day power 20, man day cost 10.
| Step | Source | Stage | Change | Running value |
|---|---|---|---|---|
| Base | Siege engine construction progress per hour | base | 0.0833 | |
| 1 | Salvager | factor +30% | +0.0250 | 0.1083 |
| 2 | Faster siege engine production | factor +10% | +0.0084 | 0.1167 |
| Result | Siege engine construction progress per hour | 0.1167 |
With these inputs, siege engine construction progress per hour is 0.1167.
300 militia give +30%, the skill effect +10%, so the engine gains 0.1167 of its build per hour.
Which one? Foreman helps mangonels and trebuchets and adds prosperity for every finished project; Salvager helps ballistas and speeds up a besieged town's engine building in proportion to its militia.
Tier 6 (Engineering 150): Siege Engineer or Stonecutters
Siege Engineer
- Primary, +30% hit points for defensive siege engines (governor;
works). Every engine of the defenders of the town or castle you govern has 30% more hit points. The governor does not need to be in the settlement. - Secondary, fire versions of siege engines can be built (engineer;
differs). Only for the player's party: the fire ballista and fire mangonel appear in your siege production menu when you besiege, and the fire ballista and fire catapult when you defend. When you defend, the engineer of your own party counts, not the town's governor. AI lords build fire engines without any perk, so an AI holder gains nothing from it.
Stonecutters
- Primary, +30% build speed for fortifications, aqueducts and barracks (governor;
differs). Aqueducts are not included: the current project has to be the Fortifications or the Barracks of the town or castle. The governor has to be in the settlement. - Secondary, fire versions of siege engines can be built (engineer;
differs). The same as Siege Engineer's secondary: either perk unlocks the fire engines, for the player's party only.
Which one? Both unlock the fire engines in your siege menu. Siege Engineer adds hit points to a governed fortification's defensive engines; Stonecutters speeds up fortifications and barracks in a governed settlement.
Tier 7 (Engineering 175): Battlements or Camp Building
Battlements
- Primary, +1 prebuilt ballista when you set up a siege camp (engineer;
differs). When the engineer of the siege camp's leading party holds the perk, the camp starts with one ballista already built. The count is a fixed one, not read from the perk's value, so the result matches the tooltip. - Secondary, +100 maximum food reserve in the governed settlement (governor;
differs). It adds 100 to the food stock effect of a castle's Granary or a town's Warehouse. Both start at level 0, so the perk does nothing until that building is built to level 1 or higher. The governor has to be in the settlement.
Camp Building
- Primary, −50% army cohesion loss while besieging (army commander;
works). While the army you lead is besieging, it loses cohesion half as fast. - Secondary, −20% casualty chance from siege bombardments (engineer;
differs). Bombardment of your troops is not affected. What the game does: when one of your side's siege engines is destroyed, a roll decides whether its crew takes casualties (2 troops by default). That chance starts at 1, so casualties are certain; Camp Building takes 0.2 off it, to 0.8.
Which one? Battlements gives a besieging camp one prebuilt ballista and a governed settlement more food stock once its Granary or Warehouse is built; Camp Building slows an army's cohesion loss in a siege and lowers the chance that a destroyed engine costs you troops.
Tier 8 (Engineering 200): Apprenticeship or Engineering Guilds
Apprenticeship
- Primary, +5 experience to troops when a siege engine is built (engineer;
works). Each time your side finishes an engine, every regular troop in the engineer's party gets 5 experience. Heroes get nothing, and only the engineer's own party gets it, not the whole siege side. - Secondary, +1% prosperity gain for each project (governor;
works). The daily prosperity change of the governed settlement goes up by 1% for every building of at least level 1 that is not a daily project. It only scales gains: on a day the prosperity change is negative, it adds nothing. The governor has to be in the settlement.
Engineering Guilds
- Primary, +1 recruitment slot at artisan notables (engineer;
differs). When you recruit from an artisan notable, you can reach one more volunteer slot. The slots are capped at 6, so the extra slot is lost once you already reach the cap. The perk is read from the engineer of the recruiting hero's party. - Secondary, +25% wall hit points in the governed settlement (governor;
works). The walls of the town or castle you govern have 25% more hit points. The governor does not need to be in the settlement.
Which one? Apprenticeship trains your party during sieges and raises prosperity gains in a governed settlement with many buildings; Engineering Guilds adds a recruit slot at artisans below the cap and adds 25% to a governed settlement's wall hit points.
Tier 9 (Engineering 225): Improved Tools or Metallurgy
Improved Tools
- Primary, +20% siege camp preparation speed (engineer;
works). While your side's siege camp is not yet built, every engine is built 20% faster. During that time Scaffolds and Torsion Engines are skipped for the same engineer; once the camp is built, they apply again and Improved Tools stops. - Secondary, +5% melee damage by troops in your formation (captain;
works). Every melee hit by a troop of the captain's formation does 5% more damage. The captain's own hits do not count.
Metallurgy
- Primary, +30% chance to remove negative modifiers on looted items (engineer;
differs). After a won battle, each looted item with a modifier that lowers its price ("Rusty", "Cracked" and so on) has a 30% chance to come out as the plain item, per unit. The perk is read from the engineer of the looting party. For the player's party, loot taken from the enemy's fallen troops is rolled twice: once when it is taken and again when the loot is collected, so those items get two 30% rolls. - Secondary, +5 armor for troops in your formation (captain;
differs). Every troop of the captain's formation gets +5 armor on head, body, arms and legs, mounted or on foot. Broader than the tooltip: the +5 is added even to a body part with no armor piece worn there.
Which one? Improved Tools speeds up engines while the camp is still being built and adds melee damage for a captain's formation; Metallurgy cleans up loot and gives a captain's formation +5 armor on head, body, arms and legs.
Tier 10 (Engineering 250): Architectural Commissions or Clockwork
An engine's reload time on the campaign map is 1440 minutes (one day) divided by its rate of fire per day, rounded. A +25% rate of fire makes the reload time 1 ÷ 1.25 as long.
Architectural Commissions
- Primary, +25% reload speed for mangonels and trebuchets (engineer;
works). Mangonels, fire mangonels and trebuchets of the engineer's side fire 25% more often. - Secondary, +20 gold per day for daily projects (governor;
works). While the governed settlement has a daily project running, it pays 20 more gold a day. The governor has to be in the settlement.
Clockwork
- Primary, +25% reload speed for ballistas (engineer;
works). Ballistas and fire ballistas of the engineer's side fire 25% more often. - Secondary, +20% effect from boosting projects in the governed town (governor;
works). Each boost you buy for a project in the town you govern adds 20% more construction, rounded. Towns only; the governor does not need to be in the town.
Which one? Architectural Commissions speeds up mangonels and trebuchets and adds daily gold from daily projects; Clockwork speeds up ballistas and strengthens project boosts in a governed town.
Tier 11 (Engineering 275): Masterwork
- +1% bombardment damage for every Engineering point above 250 (engineer;
differs). Two differences from the tooltip. The perk and the Engineering skill are both read on the party leader of the side's effective siege party, not on its engineer. It also applies only to shots at the walls or at ranged engines, not at troops. It works on either side of a siege.
Masterwork = 1% × (party leader's Engineering − 250)
- Party leader's Engineering: the skill of the leader of the side's effective siege party. At 250 or below it adds nothing.
Worked example. A besieger trebuchet with damage 100 (an example value) fires at the walls. The engineer has Wall Breaker; the party leader has Masterwork and Engineering 275:
A besieger trebuchet with damage 100 (an example value) fires at the walls; the besieger party's engineer has Wall Breaker, and the party leader has Masterwork and Engineering 275. Inputs: engine damage 100.
| Step | Source | Stage | Change | Running value |
|---|---|---|---|---|
| Base | Bombardment damage of a ranged siege engine shot | base | 100.0000 | |
| 1 | Masterwork | factor +25% | +25.0000 | 125.0000 |
| 2 | Wall Breaker | factor +25% | +25.0000 | 150.0000 |
| Result | Bombardment damage of a ranged siege engine shot | 150.0000 |
With these inputs, bombardment damage of a ranged siege engine shot is 150.0000.
25 points above 250 give +25%, Wall Breaker another +25%, so the shot does 150.0000 damage.
Skill effects
These come from the Engineering skill itself, no perk needed.
- Faster siege engine production, +0.1% per point (engineer;
works). Engines of a side are built 0.1% faster per point of Engineering of that side's engineer: +20% at Engineering 200. It applies to besiegers and defenders alike; on the defending side the governor's Engineering does not count, only the engineer's. See the Torsion Engines and Salvager examples. - Faster building production, +0.25% per point (governor;
works). Projects in the governed town or castle are built 0.25% faster per point of the governor's Engineering: +50% at Engineering 200 (see the Military Planner example). The governor has to be in the settlement. A second place in the game reads this effect only to write the governor's tooltip text (ui_only).
What the skill level itself does
The game also reads your Engineering level directly, without any perk. Effects that depend on any skill level are listed once in the skills guide.
| What it affects | What the level does | Level needed | Conditions | Verdict |
|---|---|---|---|---|
| AI governor choice score of a hero | AI clans pick a governor by the score 0.3 × Tactics + 0.9 × Charm + 0.8 × Engineering + 2 × Steward + 1.2 × Trade + Leadership (raw levels). | — | — | works |
| Incident may trigger for the player | Siege incidents can trigger for you only once your Engineering reaches the threshold (and your party is besieging). | Engineering at least 20 (At the Breach) or 30 (Mining) | Hero: main hero; map state: besieging | works |
| Skill XP from an incident option | The skill XP of an incident option (Trade, Roguery or Engineering) is multiplied by your learning rate from attribute and focus, but never reduced below ×1. | — | Hero: main hero | works |
| Defender party score for the effective siege party | Each defending party is scored by its engineer's Engineering; the party with the highest score becomes the defender's effective siege party. | — | Role: engineer; siege side: defender | works |
| Tavern keeper companion recommendation score | For party-role recommendations the score is the candidate wanderer's level in the role's skill (Scouting, Engineering, Medicine, Steward, Boatswain or Shipmaster). | — | — | works |
Who the perks work for
Who counts as you, a relative or a wanderer, and why some halves skip one of them, is explained in the Skills guide.
Every other Engineering perk half and skill effect works for every hero: you, relatives and wanderers.
| Perk | Half | Works for | Where the hero has to be |
|---|---|---|---|
| Dungeon Architect | secondary | relatives and wanderers, not you | governor |
| Siegeworks | secondary | relatives and wanderers, not you | governor |
| Carpenters | secondary | relatives and wanderers, not you | governor |
| Military Planner | secondary | relatives and wanderers, not you | governor |
| Dreadful Besieger | primary | relatives and wanderers, not you | governor |
| Foreman | secondary | relatives and wanderers, not you | governor |
| Salvager | secondary | relatives and wanderers, not you | governor |
| Siege Engineer | primary | relatives and wanderers, not you | governor |
| Stonecutters | primary | relatives and wanderers, not you | governor |
| Battlements | secondary | relatives and wanderers, not you | governor |
| Apprenticeship | secondary | relatives and wanderers, not you | governor |
| Engineering Guilds | secondary | relatives and wanderers, not you | governor |
| Architectural Commissions | secondary | relatives and wanderers, not you | governor |
| Clockwork | secondary | relatives and wanderers, not you | governor |
| Faster building production | — | relatives and wanderers, not you | governor |
All Engineering effects
Every effect site of the Engineering perks, skill effects and skill level. Values are what each site applies; a value that grows with skill is shown at the perk's required skill (skill effects and skill levels: per skill point). ×N marks N identical sites.
| Perk | Half | Game number | Stage | Value | Conditions | Verdict |
|---|---|---|---|---|---|---|
| Scaffolds | primary | Siege engine construction progress per hour | factor | +10% | Role: engineer; siege engine: non ranged | works |
| Scaffolds | secondary | Shield hit points | factor | +30% | Item: offhand shield; role: personal | differs |
| Torsion Engines | primary | Siege engine construction progress per hour | factor | +10% | Role: engineer; siege engine: ranged | works |
| Torsion Engines | secondary | Blow damage after attacker amplifications | add | +3 | Item: bolts; role: personal | works |
| Dungeon Architect | primary | Siege bombardment hit chance of a ranged engine shot | factor | -25% | Role: engineer; siege side: attacker; siege engine: target ranged engines | differs |
| Dungeon Architect | secondary | Daily escape chance of a hero prisoner | factor | -25% | Hero: prisoner; role: governor; settlement: town or castle | differs |
| Siegeworks | primary | Maximum hit points of a siege engine | factor | +10% | Role: engineer; siege engine: ranged | works |
| Siegeworks | secondary | Catapults prebuilt in a besieged fortification | add | +1 | Role: governor; settlement: fortification; siege side: defender | differs |
| Carpenters | primary | Maximum hit points of a siege engine | factor | +33% | Role: engineer; siege side: attacker; siege engine: non ranged | works |
| Carpenters | secondary | Daily construction power of a town or castle | factor | +12% | Role: governor; settlement: town | works |
| Military Planner | primary | Missile ammo amount per slot | factor | +50% | Item: consumable weapon; mission: siege; role: engineer | works |
| Military Planner | secondary | Daily construction power of a town or castle | factor | +25% | Role: governor; settlement: castle | works |
| Dreadful Besieger | primary | Siege bombardment hit chance of a ranged engine shot | factor | +10% | Role: governor; siege side: defender; siege engine: target ranged engines | differs |
| Dreadful Besieger | secondary | Blow damage after attacker amplifications | factor | +5% | Item: bolts; role: captain | works |
| Wall Breaker | primary | Bombardment damage of a ranged siege engine shot | factor | +25% | Role: engineer; siege side: attacker; siege engine: target wall | works |
| Wall Breaker | secondary | Blow damage after attacker amplifications | factor | +10% | Attack: shield hit; role: captain | works |
| Foreman | primary | Siege bombardment hit chance of a ranged engine shot | factor | +10% | Role: engineer; siege engine: onager or trebuchet or fire onager | works |
| Foreman | secondary | Town or castle prosperity | add | +100 | Role: governor | works |
| Salvager | primary | Siege bombardment hit chance of a ranged engine shot | factor | +20% | Role: engineer; siege engine: ballista or fire ballista | works |
| Salvager | secondary | Siege engine construction progress per hour | factor | +0.1% × militia | Role: governor; siege side: defender | works |
| Siege Engineer | primary | Maximum hit points of a siege engine | factor | +30% | Role: governor; siege side: defender | works |
| Siege Engineer | secondary | Fire siege engines offered in the player's siege production menu | override | on | Party: main party; role: engineer; siege side: attacker; siege engine: fire ballista or fire onager | differs |
| Siege Engineer | secondary | Fire siege engines offered in the player's siege production menu | override | on | Party: main party; role: engineer; siege side: defender; siege engine: fire ballista or fire catapult | differs |
| Stonecutters | primary | Daily construction power of a town or castle | factor | +30% | Role: governor; settlement: fortification | differs |
| Stonecutters | secondary | Fire siege engines offered in the player's siege production menu | override | on | Party: main party; role: engineer; siege side: attacker; siege engine: fire ballista or fire onager | differs |
| Stonecutters | secondary | Fire siege engines offered in the player's siege production menu | override | on | Party: main party; role: engineer; siege side: defender; siege engine: fire ballista or fire catapult | differs |
| Battlements | primary | Ballistas prebuilt in a new besieger camp | add | +1 | Role: engineer; siege side: attacker | differs |
| Battlements | secondary | Effect amount of one building for one building effect | add | +100 | Role: governor; settlement: fortification | differs |
| Camp Building | primary | Army daily cohesion change | factor | -50% | Party: in army; role: army commander; siege side: attacker | works |
| Camp Building | secondary | Chance that a destroyed siege engine kills its crew | add | -0.2 | Role: engineer | differs |
| Apprenticeship | primary | XP granted to party troops by an event | add | +5 × troops | Hero: not hero; role: engineer | works |
| Apprenticeship | secondary | Daily prosperity change of a town or castle | factor | +1% × projects | Role: governor | works |
| Engineering Guilds | primary | Highest volunteer slot index a hero can recruit from a notable | add | +1 | Role: engineer | differs |
| Engineering Guilds | secondary | Maximum wall hit points of a fortification | multiply | ×1.25 | Role: governor; settlement: fortification | works |
| Improved Tools | primary | Siege engine construction progress per hour | factor | +20% | Role: engineer | works |
| Improved Tools | secondary | Blow damage after attacker amplifications | factor | +5% | Item: melee weapon; role: captain | works |
| Metallurgy | primary | Chance to strip a negative modifier from looted items | override | set to 0.3 | Role: engineer | works |
| Metallurgy | primary | Chance to strip a negative modifier from looted items | override | set to 0.3 | Party: main party; role: engineer | differs |
| Metallurgy | secondary | Agent arm armor | add | +5 | Role: captain | differs |
| Metallurgy | secondary | Agent head armor | add | +5 | Role: captain | differs |
| Metallurgy | secondary | Agent leg armor | add | +5 | Role: captain | differs |
| Metallurgy | secondary | Agent torso armor | add | +5 | Role: captain | differs |
| Architectural Commissions | primary | Campaign rate of fire of a ranged siege engine | factor | +25% | Role: engineer; siege engine: onager or trebuchet or fire onager | works |
| Architectural Commissions | secondary | Daily gold from town projects | add | +20 | Role: governor | works |
| Clockwork | primary | Campaign rate of fire of a ranged siege engine | factor | +25% | Role: engineer; siege engine: ballista or fire ballista | works |
| Clockwork | secondary | Construction power bought by one boost | multiply | ×1.2 | Role: governor; settlement: town | works |
| Masterwork | primary | Bombardment damage of a ranged siege engine shot | factor | +1% × max(0, leader skill - 250) | Role: engineer; siege engine: target wall or ranged engines | differs |
| Faster siege engine production | — | Siege engine construction progress per hour | factor | +0.1% per point | Role: engineer | works |
| Faster building production | — | Daily construction power of a town or castle | factor | +0.25% per point | Role: governor | UI only |
| Faster building production | — | Daily construction power of a town or castle | factor | +0.25% per point | Role: governor | works |
| Skill level (any skill) | — | Agent effective skill in battle | base | skill value | — | works |
| Skill level | — | AI governor choice score of a hero | add | +0.3 × tactics skill + 0.9 × charm skill + 0.8 × engineering skill + 2 × steward skill + 1.2 × trade skill + leadership skill | — | works |
| Skill level (any skill) | — | Skill a hero inherits on coming of age | base | +1 per point | — | works |
| Skill level (any skill) | — | Heir selection points of a clan member | add | +5 | — | works |
| Skill level | — | Incident may trigger for the player | override | off | Hero: main hero; map state: besieging | works |
| Skill level | — | Skill XP from an incident option | multiply | ×max(learning rate, 1) | Hero: main hero | works |
| Skill level (any skill) | — | Maximum troops lost on an issue's alternative solution | multiply | ×max(0.2, min(0.8, trunc(issue required skill / skill) × 0.1)) | Hero: player clan | works |
| Skill level (any skill) | — | Days an issue's alternative solution takes | add | +2 × min(10, trunc(issue required skill / skill)) | Hero: player clan | works |
| Skill level (any skill) | — | Failure risk of an issue's alternative solution | add | -0.005 per point | Hero: player clan | works |
| Skill level (any skill) | — | Troops required for an issue's alternative solution | multiply | ×max(0.2, min(1.2, issue required skill / skill)) | Hero: player clan | works |
| Skill level (any skill) | — | Skill is high enough for a perk reset | override | on | Hero: player clan | works |
| Skill level (any skill) | — | Gold cost to reset the perks of a skill | add | +40 per point | Hero: player clan | works |
| Skill level | — | Defender party score for the effective siege party | add | +1 per point | Role: engineer; siege side: defender | works |
| Skill level (any skill) | — | Persuasion success multiplier | factor | min(0.2, floor(skill / 250) × 0.2) | Hero: main hero | works |
| Skill level | — | Tavern keeper companion recommendation score | base | +1 per point | — | works |
Practical tips
- Siege perks follow the lead party. Most engineer halves read the engineer of the side's effective siege party. If another party leads your side, its engineer's perks apply instead of yours, except Military Planner (your own party), the fire engines (the player's party), Engineering Guilds (the recruiting hero's party) and Metallurgy (the looting party).
- If you want fire engines in your siege menu, either Siege Engineer or Stonecutters unlocks them, for your own party only.
- If your engineer has Improved Tools, Scaffolds and Torsion Engines only start to count once the siege camp is built.
- Masterwork reads the party leader. If your engineer is a companion, you need the perk and Engineering above 250 yourself.
- Governor halves differ on presence. Carpenters, Military Planner, Stonecutters, Salvager, Battlements, Apprenticeship, Dungeon Architect's prisoners, Architectural Commissions' daily gold and the Faster building production skill effect need the governor in the settlement; the others do not.
- If you govern a castle, Military Planner adds +25% construction; Carpenters and Clockwork only work in towns.
- Battlements' food bonus needs a Granary or Warehouse built to level 1 or higher.
- If you recruit from artisans often, Engineering Guilds adds a slot only while you are below the cap of 6.