Document.Engineering

@elite-dangerous-almanac/core / Engineering

Engineering

The engineering API answers two questions: what can I put on this module, and what does it do to the stats. The menu is also the validation gate, so an editor and its menu cannot give different answers.

The menu is the gate

Availability is a property of the module, not of the blueprint. A Pulse Laser accepts the Efficient blueprint and a Rail Gun does not, and two modules whose blueprints overlap may still offer different experimental effects. So ships/engineering-options groups the modules and each group lists what it offers.

import {
    getBlueprintsForModule,
    getExperimentalsForModule,
} from '@elite-dangerous-almanac/core/ships/engineering-options';

getBlueprintsForModule('Hpt_PulseLaser_Fixed_Small'); // the recipes this weapon takes
getExperimentalsForModule('Hpt_PulseLaser_Fixed_Small'); // the effects it takes

applyBlueprint reads that same catalogue and refuses a recipe it does not list for that module. That is the point: "what can I put on this?" and "may I put this on it?" are answered from one source, so a menu that offers a recipe the editor would reject is not a state this library can reach.

ShipLoadout includes the menu catalogue whether or not a consumer calls these methods. Using one catalogue keeps the editor and menu consistent.

Not every module engineers. The catalogue groups 1028 of the 1199 modules; the rest take nothing — whole families like fuel tanks, passenger cabins and limpet controllers, plus individual modules upstream denies every recipe. A module with no group is not a gap in the data.

Why there is no family map

Inferring and comparing families from module and blueprint symbols refuses recipes on 52 modules and disagrees with 76 entries in a 1902-entry build corpus. The failures come from the inference rather than the data — the Hatch Breaker Limpet Controller's symbol is Int_DroneControl_ResourceSiphon, which no "hatchbreaker" prefix rule matches, and the Caustic Sink Launcher's symbol says causticsink where its group is the heat sink launchers'. A per-module menu has nothing to infer, and two hand-maintained answers to one question can drift. The API therefore uses only the per-module menu.

Rolling a recipe

A blueprint grade bounds each modifier, and the engineering quality roll picks a point in that range: v = min + (max − min) × quality. An experimental effect adds a fixed contribution on top. computeModifiers folds every contribution onto the module's base stats and hands back journal-style modifiers.

import { computeModifiers } from '@elite-dangerous-almanac/core/ships/engineering';
import { getBlueprintGrade } from '@elite-dangerous-almanac/core/ships/blueprints';
import { getExperimentalEffect } from '@elite-dangerous-almanac/core/ships/experimental-effects';

const mods = computeModifiers(
    { FSDOptimalMass: 4670 },
    getBlueprintGrade('FSD_LongRange', 5)!,
    1, // quality: 0 is the worst roll, 1 the best
    getExperimentalEffect('special_fsd_heavy')!,
);
// -> [{ Label: 'FSDOptimalMass', Value: 7528.04, OriginalValue: 4670 }]

Each contribution names a journal Label and an apply method — multiplicative (the percentages compound), additive (flat reinforcement) or overwrite (the value replaces the base). Two behaviors apply on top of those methods:

• Percentages of a multiplier. Hull boost, shield boost and the four resistances compound on their multiplier rather than on the stat, whichever method the recipe names. Build metrics works through what that does to a figure.
• A capability rather than a number. Anti-Guardian Zone Resistance produces { Label: 'GuardianModuleResistance', ValueStr: 'Active' }; its displayed +100% is not folded as a value, and effective module stats expose the granted boolean instead.

On a build, all of this is one call, and it recomputes the derived stats — a weapon's rate of fire, for instance — that follow from what the recipe changed:

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';

const build = ShipLoadout.empty('Anaconda');

build.availableBlueprints('FrameShiftDrive'); // what this mount can take
build.availableExperimentalEffects('FrameShiftDrive');

The three accommodations

The gate makes exactly three allowances beyond the menu. They are applied in a fixed order — journal spelling, then the pre-engineered route, then the generic spelling — and only the first can change which recipe an accepted id names.

The journal spelling of a menu entry. Where the game writes one BlueprintName for two different recipes, the module's own group carries the map from that id to the entry it names. Only the three utility-scanner groups need one. This is pinned data rather than inference, because unlike the generic spellings the two ids do not describe the same modification.

The generic spelling. Where a modification applies to several families, the game writes a family-specific id and the catalogue lists that one — but a build authored elsewhere may carry the generic Misc_* id. Both are accepted, because both name the same recipe: their grades touch the same labels by the same methods.

The alias is directional, and that is what keeps it safe. A generic id stands in for a family's id, never for another generic one. Misc_ChaffCapacity and Misc_HeatSinkCapacity are both "Ammo capacity" over the same three labels, but they roll different amounts of different ammunition, so neither may substitute for the other.

The pre-engineered route. Most Operations keys belong to a module bought already engineered, so no menu lists one and the menu check alone would refuse all of them everywhere. ships/pre-engineered names which module each arrives on, and the gate accepts such a recipe on the non-final module sold carrying it and nowhere else — RailGun_LongShot resolves on the medium rail gun, not on the small one.

This route covers the climb, not the purchase. A Mercenary module arrives at grade 1 and its recipe publishes grades 2–5, the grades an engineer can still add; the grade it was sold at cannot be reproduced through this route, and a variant marked engineeringLocked never takes it at all.

Pre-engineered modules

Use ships/pre-engineered to find a variant and ships/pre-engineered-stats to resolve its fitted stats.

import { getPreEngineeredVariants } from '@elite-dangerous-almanac/core/ships/pre-engineered';
import { getPreEngineeredStats } from '@elite-dangerous-almanac/core/ships/pre-engineered-stats';

const variants = getPreEngineeredVariants('Hpt_BasicMissileRack_Fixed_Medium');
const resolved = variants[0] ? getPreEngineeredStats(variants[0]) : null;
resolved?.symbol;

The API documentation owns the record and resolution semantics: see PreEngineeredVariant, getPreEngineeredVariants, and getPreEngineeredStats.

What a roll costs

Costs are a separate catalogue from mechanics, on their own subpaths, so a build editor that never prices anything does not bundle the shopping lists. ships/blueprints answers what a recipe does; ships/blueprint-costs answers what it takes.

import { getBlueprint } from '@elite-dangerous-almanac/core/ships/blueprints';
import { getBlueprintCost } from '@elite-dangerous-almanac/core/ships/blueprint-costs';
import { rollsForGrade } from '@elite-dangerous-almanac/core/ships/engineering';

getBlueprint('FSD_LongRange'); // the mechanics: every grade's features
getBlueprintCost('FSD_LongRange', 5); // materials for the whole climb, grades 1–5
getBlueprintCost('FSD_LongRange', 5, 4); // grade 5 alone, from a grade-4 module
rollsForGrade(5); // rolls to fill the grade's progress bar

A grade costs its recipe once per roll and grade g takes g rolls, so the climb is weighted rather than a plain sum — which is what getBlueprintCost folds in for you.

An experimental effect is a separate single application, on its own subpath again, and sumMaterials folds the two bills into one:

import { getBlueprintCost } from '@elite-dangerous-almanac/core/ships/blueprint-costs';
import { getExperimentalEffectCost } from '@elite-dangerous-almanac/core/ships/experimental-effect-costs';
import { sumMaterials } from '@elite-dangerous-almanac/core/ships/engineering';

const grand = sumMaterials(
    getBlueprintCost('Weapon_LongRange', 5) ?? [],
    getExperimentalEffectCost('special_focused') ?? [],
);
grand.length;

Pricing the remaining upgrade on a module bought pre-engineered is the same call with the grade it arrived at as the third argument. On a reward variant it is not: those carry hand-set overrides no blueprint grants, so the ordinary material recipe prices ordinary engineering rather than the reward.

Next

• Build metrics — what these modifiers do to power, shields, armour, weapons and range.
• Building an outfitting screen
• Reading a player journal
• Complete API reference