position.md

title	position
description	Read the model origin in another model’s solved local frame.
sourceReview	packageVersion sources 0.0.1-alpha.16 path sha256 packages/core/src/library/runtime.ts dcee3d2388a9b7b3819bb4897edd894463daa0e5b519e832a3349fac98c3bff8 path sha256 commit packages/core/src/library/spatial.ts 810c4fa69352c26c32fb04a0e7867f6327698e02f3212669f17d777784322a78 69d231fb775befdb3cd098291b4097ccd52d8966
sidebar	hidden true
head	tag content title position — Code3D TypeScript API reference

Read the model origin in another model’s solved local frame.

Example

import {on, box, group, offset} from '@code3d/core';

const base = box(20, 4, 20);
const part = box(8, 12, 4).relate(() => [on(base.up), offset(20, 0, 0)]);
export const size = part.bounds().size; // [8, 12, 4]
export const origin = part.position(base); // [20, 8, 0]
export const minimum = part.bounds(base).minimum; // [16, 2, -2]
export default group([base, part]);

Signature

model.position(relativeTo: Model): Vec3;
type Vec3 = readonly [number, number, number];

Import the functions and named types from @code3d/core.

Required reference model

Every model kind, including groups, supports position. relativeTo is required and must be a model; the result is an XYZ coordinate tuple in its local frame. Existing relations are solved, and a unique member occurrence inside a nested reference group is respected. It is neither camera coordinates nor an implicit application-global position.

The example's part origin is [20, 8, 0] in the base frame: the contact puts its half-height 6 above the base top at Y = 2, followed by an X offset of 20. part.position(part) is always [0, 0, 0].

Origin versus geometry

Position measures the model's coordinate origin, not its geometric center or minimum bound. A point([10, 0, 0]) model still has origin zero in its own frame; its actual vertex is at X = 10. Origin edits change the relationship between geometry and the frame, so use bounds or distance when the geometry itself is the measurement target.

Unrelated models use coincident origins and matching axes. A group keeps its composition frame. A bare source with multiple occurrences in a reference group is ambiguous and throws; select an unambiguous instance or create distinct part values. position is a reserved model member name and cannot be exposed over.

Returned value

The result is ordinary numeric data in model units. Reading it changes neither model. It reflects relationships already attached at the call; constraints still being constructed inside a relate callback are not yet attached. Creating additional related model values later does not update a previously stored tuple.