# `Materials.create`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `configurator-runtime.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Method of [`Materials`](Materials.md) · stable · since 2.0.0 · called as `session.materials.create`

```ts
create(spec: MaterialSpec, options?: {
  signal?: AbortSignal;
}): Material<C>;
```

Lifecycle call: immediate. Owned by the session; disposed when `signal` aborts, at once when it
already has (pass [`collection.signal`](Collection.signal.md) to dispose it with a collection). Wear it through a rule
([`find(q).set({ material })`](PartActions.set.md)).
Errors: throws HoloInputError on an invalid spec.

**Default:** options.signal undefined

## Options

Through [`Session`](Session.md):

| Option | Type | Default | What it does |
| --- | --- | --- | --- |
| `signal` | `AbortSignal` | — |  |

Through [`Tx`](Tx.md):

| Option | Type | Default | What it does |
| --- | --- | --- | --- |
| `signal` | `AbortSignal` | — |  |

## Abort (`signal`)

This call is a creator (`SignalOption.signal`, [the kinds of call](../read-this-first.md#conventions)).

> A creator (`collection` for a new name, `materials.create`, `on`, `onFrame`, `beforeCommit`, `follow`, `input.drag`, `labs.lightLinking`) given a signal already aborted returns at once, already ended: a `Collection` or `Material` reading `disposed: true` that holds no content and no live name, or a registration that never runs and whose disposer does nothing.
>
> It records no Problem for the abort and throws only what it would throw anyway, as the DOM's `addEventListener` with an aborted signal adds nothing (spec section 6.5).

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `create` names no product |
| 2. A precedent | not recorded: no ledger row (coverage.json) names this member or its owner |
| 3. Two apps, or labs | not recorded: no ledger row names this member or its owner |
| 4. The cheaper fix first | not recorded per member (Appendix B decides it per need) |