Query: HalfEdge

Half-edge queries — walk and read a single BREP half-edge. A HalfEdgeHandle is minted by walking from a brep/face/edge/vertex handle; it is session-ephemeral and goes stale on undo/redo/re-topologize. Accessed via snaptrude.core.geom.query.halfedge.

The kind token is all-lowercase "halfedge" (no camelCase namespaces). Traversals (getNext/getPrev/getFlip) return null on a boundary or a malformed chain rather than throwing — reads never throw.

Every method takes a single positional HalfEdgeHandle argument.

Functions

getNext(halfEdge)

Get the next half-edge around the face loop.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to walk from
• Returns: HalfEdgeHandle | null — The next half-edge, or null on a malformed chain
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

const { face, halfedge } = snaptrude.core.geom.query;

// Walk the outer loop of a face
const start = await face.getHalfEdge(someFace);
let he = start;
do {
  const vertex = await halfedge.getVertex(he);
  // ...use vertex...
  he = await halfedge.getNext(he);
} while (he !== null && he !== start);

---

getPrev(halfEdge)

Get the previous half-edge around the face loop.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to walk from
• Returns: HalfEdgeHandle | null — The previous half-edge, or null on a malformed chain
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

---

getFlip(halfEdge)

Get the flip (opposite) half-edge of the shared edge.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to flip
• Returns: HalfEdgeHandle | null — The flip half-edge, or null on a boundary
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

---

getVertex(halfEdge)

Get the tail vertex of a half-edge.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to read
• Returns: VertexHandle — The tail vertex
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

---

getEdge(halfEdge)

Get the edge of a half-edge.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to read
• Returns: EdgeHandle — The owning edge
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

---

getFace(halfEdge)

Get the face of a half-edge.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to read
• Returns: FaceHandle — The owning face
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

---

isOnBoundary(halfEdge)

Test whether a half-edge lies on the brep boundary (has no flip).

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to test
• Returns: boolean — true if on the boundary, otherwise false
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

---

isForward(halfEdge)

Test whether a half-edge is the forward (primary) half-edge of its edge — i.e. edge.getHalfEdge() === thisHalfEdge.

• Parameters:
  • halfEdge: HalfEdgeHandle — The half-edge to test
• Returns: boolean — true if forward, otherwise false
• Throws: HandleInvalidError if halfEdge is invalid, stale, or foreign

const { halfedge } = snaptrude.core.geom.query;

const onBoundary = await halfedge.isOnBoundary(he);
const forward = await halfedge.isForward(he);

Errors

Failed calls reject with a typed PluginError — see Error Handling. Conditions specific to this namespace:

Code	Thrown by	When	details
HANDLE_INVALID	all methods	The half-edge handle is invalid, foreign, or stale (undo/redo/re-topologize invalidates it)	—

Beyond handle resolution these reads never throw — getNext/getPrev/getFlip return null on a boundary or malformed chain, as noted above.