flip-reverse.md

title	flip / reverse
description	Reverse reference orientation without changing finite geometry or parameter points.
sourceReview	packageVersion sources 0.0.1-alpha.16 path sha256 packages/core/src/library/runtime.ts dcee3d2388a9b7b3819bb4897edd894463daa0e5b519e832a3349fac98c3bff8 path sha256 commit packages/core/src/library/topology.ts f9f0d048fe30cc80046a25123aa8101ca51e85cdb5b2e66260c6a68f43f84715 67228dd8559d584852df7bfbd47ed89f1d8003e9 path sha256 commit packages/core/src/library/spatial.ts 810c4fa69352c26c32fb04a0e7867f6327698e02f3212669f17d777784322a78 69d231fb775befdb3cd098291b4097ccd52d8966
sidebar	hidden true
head	tag content title flip / reverse — Code3D TypeScript API reference

Reverse reference orientation without changing finite geometry or parameter points.

Example

import {line, rectangle} from '@code3d/core';

export const segment = line([0, 0, 0], [10, 0, 0]);
export const backward = segment.reverse();
export const sheet = rectangle(12, 8);
export const downward = sheet.flip();

Complete example: topology and references.

Signature

lineAnchor.reverse(): typeof lineAnchor;
faceAnchor.flip(): typeof faceAnchor;
bound.flip(): Bound;
edgeModel.reverse(): Edge;
faceModel.flip(): Surface;

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

reverse

LineAnchor.reverse() returns a reference with opposite direction sense. An Edge retains its ID, finite curve, length and reference axes. Its start, midpoint and end still select the same underlying parameter positions; reverse does not swap those properties or reverse the stored curve geometry.

Use it when align should match opposite curve directions, or when a straight axisLine should use the opposite positive rotation sense. Point membership on a curve ignores direction, so it is unchanged. The original reference remains unchanged too.

flip

FaceAnchor.flip() returns a reference with reversed normal sense. A selected Surface keeps its ID, finite region, area, position and reference axes. It does not modify the BRep face or produce a new solid. Plane coincidence can use the opposite normal, while point-on-surface membership is unchanged.

A Bound also supports flip: its boundary stays in place and only its directed contact sense reverses. up.flip() stays on the upper boundary; it does not select the lower one.

Model shortcuts return references

EdgeModel.reverse() selects its edge and returns an Edge reference. FaceModel.flip() selects its surface and returns a Surface reference. These shortcuts do not return new edge or face models. In the example, backward.length remains 10 and downward.area remains 96. The results are useful in constraints and queries, but cannot be passed as standalone geometry children or as model inputs to extrude, sweep or thicken.

For changing local geometry, use modeling transforms on the original model. For choosing coordinate zero use the origin methods. Reversing a reference twice restores its orientation sense; reference object identity is not an equality test for geometry or topology.