Glossary

Every term that LUIDA, Cluster, or CCK uses with a specific meaning. Cross-linked from concept pages and tutorials. If something's missing, open a PR.

LUIDA-specific terms

eID — experiment ID

The unique identifier the Web Console assigns to your experiment when you register it. Format: a short alphanumeric string. You paste this into Unity (LUIDA › Configure experiment identifiers) so the Implementation Template knows which experiment its data belongs to.

qID — questionnaire ID

A 1-based position within your experiment's questionnaire list. The first questionnaire you add is qID=1, the second is qID=2. You bind a questionnaire to a state in the State Machine editor by typing its position. See Questionnaires for the full binding model.

pID — participant ID

A 1-based index identifying which participant in the current session you're talking about. pID=1 is the first participant, pID=2 the second. Stable for the duration of one session; reused across sessions for new participants.

sID — session ID

A unique identifier for one execution of the experiment. Created by the Web Console when the first eligible participant enters the world; shared by all participants in that instance. See Conditions, sessions, participants.

IDFC

Cluster's per-user identifier. Opaque to you (you can't decode it), but stable across sessions for the same user. LUIDA logs IDFC for every participant so you can identify repeat participants in your data.

Condition

The combination of variable values active for a session (between-subjects) and trial (within-subjects). Stored in the CONDITION global at runtime. See Within vs between subjects.

Trial

One pass through the trial loop of the state machine — typically Trial - Start → ... → Trial - Rest. Each trial sees one combination of within-subjects values. See State machine & trial lifecycle.

Session

One execution of an experiment by one or more participants. Begins when pNum participants pass eligibility; ends when the state machine reaches End. Sessions are LUIDA's unit of "one experimental run."

Participant

One human user who joins a Cluster instance to participate in an experiment. 1-indexed in PARTICIPANTS[] arrays. Distinguished from "user" because a single user can be a participant in multiple sessions.

State

A node in the experiment's state machine. Either fixed (Trial - Start, Trial - Rest, End) or user-defined. Identified at runtime by the integer state_currentID.

State-listening item

A GameObject in your scene that has actions configured to fire when specific states activate or deactivate. The Implementation Template's State-listening Items editor is where you wire these up. Every cell in the editor's grid is "what this item does at this state."

Customized Action

A code block (ClusterScript JavaScript) inserted inline into a state-listening item's action chain. Used when none of the predefined actions fit. See Decision tree.

Implementation Template

The Unity 2021.3.4f1 project that researchers use as a starting point for building their experiment world. This docs site is the documentation for that template. Distribute via GitHub Releases (do not clone the repo).

Web Console

The Next.js application at luida.cluster.mu where researchers register experiments, build questionnaires, upload avatars, and download data. Backed by MongoDB and AWS S3.

Recruitment World

A public Cluster world maintained by the LUIDA team. It hosts a bulletin board listing all accepting experiments. Participants enter the Recruitment World, browse, and click into individual experiments.

Experiment World

The Cluster world (one per experiment) that participants enter to actually do the study. You build it in Unity using the Implementation Template; Cluster runs many parallel instances of it.

Cluster / CCK terms

Cluster

The metaverse platform LUIDA deploys to. cluster.mu. Multi-platform (VR, desktop, mobile), free for users. Run by Cluster Inc., based in Japan.

CCK — Cluster Creator Kit

The Unity toolkit Cluster provides for building worlds. docs.cluster.mu/creatorkit. LUIDA depends on CCK 2.35.0.

ClusterScript

Cluster's JavaScript variant for in-world server-side logic. See Assets/Doc/CCK-Types.d.ts in the Implementation Template repo for the full API surface.

Item (CCK)

A GameObject with the CCK Item component attached. The unit of "interactable thing" in a Cluster world. May be in the scene at upload time or created at runtime via $.createItem.

Gimmick (CCK)

A CCK component that responds to a state change by performing some action — moving an item, playing audio, showing/hiding things. LUIDA adds custom gimmicks for research-specific behaviors (assign avatar, advance state, upload data).

Trigger (CCK)

A CCK component that fires a signal or sets a state value when something happens — being touched, being grabbed, a timer expiring. Triggers are how participant actions enter the experiment's logic.

$.groupState

Cluster's per-instance shared object cache. Server-side, in-memory, lives for the duration of the instance. LUIDA uses it for participants list, current condition, collected data scratchpad. See Reference → Signals & state keys.

callExternal

CCK's mechanism for an in-world script to make HTTP calls to a pre-configured external endpoint. LUIDA uses it for everything that needs to persist beyond a single session — talking to the Web Console.

CSEmulator

A KaomoLab tool that lets you run ClusterScript locally inside the Unity Editor (instead of having to upload to a Cluster test space). Imperfect simulator — networking and avatar systems behave slightly differently — but good for fast iteration.

CSCombiner

A KaomoLab tool that combines multiple .js files into a single ClusterScript per item. LUIDA generates many small JS files; CSCombiner stitches them.

KaomoLab

The publisher of CSCombiner and CSEmulator. Sells via Booth.pm. The tools are gitignored in the Implementation Template — you import them yourself the first time.

VRM

A standardized 3D model format for humanoid avatars. LUIDA's avatar system accepts VRM files uploaded through the Web Console. See Web Console → Avatars.

Booth.pm

Japan-based marketplace where independent creators sell digital goods, including the KaomoLab tools and many CCK-compatible avatars and assets.

Experiment-design terms

Within-subjects variable

A variable whose values every participant experiences. See Within vs between subjects.

Between-subjects variable

A variable whose values are split across participants — each participant sees only one. See Within vs between subjects.

Counterbalancing

Systematically varying the order of within-subjects conditions across participants to neutralize order effects. LUIDA does random shuffling per participant; explicit counterbalancing (Latin squares, etc.) requires a custom condition setter — see Decision tree.

IPQ — Igroup Presence Questionnaire

A 14-item Likert-scale instrument measuring sense of presence in VR. Available as a built-in template when adding a questionnaire in the Web Console.

SSQ — Simulator Sickness Questionnaire

A 16-item Likert-scale instrument measuring simulator sickness symptoms. Built-in template in the Web Console.

VEQ — Virtual Experience Questionnaire

A questionnaire measuring user experience in VR. Listed as a planned built-in template; ask the LUIDA team for current status.

NASA-TLX

The NASA Task Load Index — a workload questionnaire commonly used in HCI research. Not currently a built-in template; build it as a custom questionnaire if you need it.

Presence

A subjective sense of "being there" in a virtual environment. The construct measured by IPQ.

Simulator sickness

Nausea, disorientation, and oculomotor symptoms induced by VR or other simulators. Measured by SSQ.

Site-specific terms

MDX

Markdown with embedded JSX components. The format every page on this docs site is written in.

Mermaid

A diagramming syntax for flowcharts, sequence diagrams, etc. LUIDA Docs uses Mermaid for component diagrams — currently rendered as code blocks pending plugin wiring; will render as inline SVG once enabled.

Tailwind

The CSS framework this site uses. Class names like flex, mt-4, text-lg come from Tailwind.

Fumadocs

The Next.js-based documentation framework powering this site.

sourceOfTruth / translationStatus

MDX frontmatter fields that mark which locale (EN or JA) is the canonical version of a page, and whether the other locale is in sync. See the contributor guide.