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Simulation & Interaction

The layer that makes Arx an immersive sim rather than a dungeon crawler with good magic.

Everything is an entity with a script

Each interactive object in the game ships as a model folder plus an .asl script — there are over 3,600 of them in the retail data. Doors, chests, NPCs, food, torches, levers and traps all respond to the same event vocabulary (MAIN, COMBINE, CUSTOM, HEAR, DETECTPLAYER, LOCKPICKED, timers, and so on), and shared behaviour is pulled in as include files — lockpicking, for instance, is one lockpick.asl fragment reused by every locked object in the game.

This is the architectural reason Arx feels systemic on a nine-person budget: the simulation is thin and the scripts are many. The engine does not model fire spreading or dough rising; a script on a specific object does, once, well. The affordances are hand-authored but uniformly addressed, so they read as emergent.

Observation vs interpretation

The uniform event vocabulary is verifiable in the data. The claim that this was a deliberate cost-saving architecture is my inference from the team size, not a developer statement.

The needs clock

A single per-frame update handles regeneration, hunger and poison:

  • Life regen 0.00008 × ms × (Con + Str×0.5 + Defense) × 0.02
  • Mana regen 0.0000008 × ms × (Mind + EtheralLink) × 10
  • Hunger decays at the life-regen rate scaled by (Con + Str×0.5) × 0.5, floors at −10, and the character speaks a hunger line as it crosses 10. Below zero, the life regen term inverts into a slow drain.
  • Poison ticks as a saving throw each frame against resistPoison; a failed throw deals a third of the tick as damage and burns off poison faster than a successful one.

Hunger is therefore not a survival mechanic — it is a soft nag that converts neglect into a healing debuff. Its real function is to make food an object worth picking up, which makes kitchens, taverns and cooking worth simulating, which makes the city feel inhabited. The mechanic exists to justify the fiction, not the other way round.

Cooking and combination

Combining items is a first-class script event, which is how the famous bread-baking works: dough + heat source, performed physically in the world. Create Food (tier 3, Aam Vitae Cosum, 5 mana) is the magical shortcut. The rat-tail-in-a-pie interactions and similar oddities are individual scripts, not a crafting system with rules — there is no recipe engine to discover, only authored pairs.

Physics as a verb

Objects can be picked up, thrown, stacked, dropped to make noise (800-unit hearing radius), or moved with Telekinesis (tier 4, 0.001 mana — effectively free). Physical manipulation is how the player solves problems the stat sheet has no answer for, and it is the ancestor of every Arkane game that followed.

Touchpoints

  • → Core Loop: the verb layer is the 10-second loop
  • → Economy & Items: items are world objects before they are inventory
  • → Magic & Runes: several spells are simulation verbs in costume (Telekinesis, Create Food, Ignit, Douse)
  • → Narrative & Theme: notes, books and signs are scripted entities, so lore is placed in the world as objects

What breaks if you remove it

The genre. Without object physics and the script layer, Arx is a corridor RPG and the magic system loses the diegetic frame that makes gesture casting feel of a piece with everything else.