diff --git a/web/app/3d/craft/brep/cut-extrude.js b/web/app/3d/craft/brep/cut-extrude.js
index 9636995a..710cd0b1 100644
--- a/web/app/3d/craft/brep/cut-extrude.js
+++ b/web/app/3d/craft/brep/cut-extrude.js
@@ -3,7 +3,7 @@ import * as math from '../../../math/math'
 import Vector from '../../../math/vector'
 import {Extruder} from '../../../brep/brep-builder'
 import {BREPValidator} from '../../../brep/brep-validator'
-import * as approx from '../../../brep/approx'
+import * as stitching from '../../../brep/stitching'
 import {subtract, union} from '../../../brep/operations/boolean'
 import {Loop} from '../../../brep/topo/loop'
 import {Shell} from '../../../brep/topo/shell'
@@ -51,7 +51,7 @@ export function doOperation(app, params, cut) {
     if (cut) throw 'unable to cut plane';
     result = operand;
   }
-  approx.update(result);
+  stitching.update(result);
   const newSolid = new BREPSceneSolid(result);
   return {
     outdated: [solid],
@@ -113,10 +113,10 @@ export class ParametricExtruder extends Extruder {
   onWallCallback(wallFace, baseHalfEdge) {
     const conn = baseHalfEdge.vertexA.point.sketchConnectionObject;
     if (conn && isCurveClass(conn._class)) {
-      if (!conn.approxSurface) {
-        conn.approxSurface = new approx.ApproxSurface();
+      if (!conn.stitchedSurface) {
+        conn.stitchedSurface = new stitching.StitchedSurface();
       }
-      conn.approxSurface.addFace(wallFace);
+      conn.stitchedSurface.addFace(wallFace);
     }
   }
 }
diff --git a/web/app/3d/scene/brep-scene-object.js b/web/app/3d/scene/brep-scene-object.js
index ef8f5c63..435ddffd 100644
--- a/web/app/3d/scene/brep-scene-object.js
+++ b/web/app/3d/scene/brep-scene-object.js
@@ -1,5 +1,5 @@
 import Vector from '../../math/vector'
-import {EDGE_AUX} from '../../brep/approx'
+import {EDGE_AUX} from '../../brep/stitching'
 import {Triangulate} from '../../3d/triangulation'
 import {SceneSolid, SceneFace} from './scene-object'
 
diff --git a/web/app/3d/selection.js b/web/app/3d/selection.js
index 05a0fc48..f78f1c82 100644
--- a/web/app/3d/selection.js
+++ b/web/app/3d/selection.js
@@ -1,5 +1,5 @@
 import DPR from '../utils/dpr'
-import * as approx from '../brep/approx'
+import * as stitching from '../brep/stitching'
 
 class AbstractSelectionManager {
   
@@ -81,9 +81,9 @@ export class EdgeSelectionManager extends AbstractSelectionManager {
   select(line) {
     this._clearSilent();
     const edge = line.__TCAD_EDGE;
-    const approxCurve = edge.data[approx.EDGE_CHUNK];
-    if (approxCurve) {
-      for (let edgeChunk of approxCurve.edges) {
+    const stitchedCurve = edge.data[stitching.EDGE_CHUNK];
+    if (stitchedCurve) {
+      for (let edgeChunk of stitchedCurve.edges) {
         this.mark(edgeChunk.data['scene.edge']);
       }
     } else {
@@ -158,9 +158,9 @@ export class SelectionManager extends AbstractSelectionManager {
       return sceneFace.curvedSurfaces;
     }
     if (sceneFace.brepFace) {
-      const approxFace = sceneFace.brepFace.data[approx.FACE_CHUNK];
-      if (approxFace) {
-        return approxFace.faces.map(f => f.data['scene.face']);
+      const stitchedFace = sceneFace.brepFace.data[stitching.FACE_CHUNK];
+      if (stitchedFace) {
+        return stitchedFace.faces.map(f => f.data['scene.face']);
       }
     }
     return undefined;
diff --git a/web/app/brep/approx.js b/web/app/brep/stitching.js
similarity index 50%
rename from web/app/brep/approx.js
rename to web/app/brep/stitching.js
index 574c6532..eb60d4d7 100644
--- a/web/app/brep/approx.js
+++ b/web/app/brep/stitching.js
@@ -1,10 +1,10 @@
 import {DoubleKeyMap} from '../utils/utils'
 
-export const FACE_CHUNK = 'approx.face.chunk';
-export const EDGE_CHUNK = 'approx.edge.chunk';
-export const EDGE_AUX = 'approx.edge.aux';
+export const FACE_CHUNK = 'stitching.face.chunk';
+export const EDGE_CHUNK = 'stitching.edge.chunk';
+export const EDGE_AUX = 'stitching.edge.aux';
 
-export class ApproxSurface {
+export class StitchedSurface {
   constructor() {
     this.faces = [];   
   }
@@ -20,7 +20,7 @@ export class ApproxSurface {
   
 }
 
-export class ApproxCurve {
+export class StitchedCurve {
   constructor(surface1, surface2) {
     this.surface1 = surface1;
     this.surface2 = surface2;
@@ -33,7 +33,7 @@ export class ApproxCurve {
   }
   
   equals(other) {
-    return other instanceof ApproxCurve &&
+    return other instanceof StitchedCurve &&
         
       ((this.surface1 == other.surface1 &&
         this.surface2 == other.surface2) ||
@@ -47,29 +47,29 @@ export class ApproxCurve {
 export function update(shell) {
   const index = new DoubleKeyMap();
   for (let face of shell.faces) {
-    const approxSurface = face.data[FACE_CHUNK];
-    if (approxSurface) {
-      approxSurface.clear();
+    const stitchedSurface = face.data[FACE_CHUNK];
+    if (stitchedSurface) {
+      stitchedSurface.clear();
     }
   }
   for (let face of shell.faces) {
-    const approxSurface = face.data[FACE_CHUNK];
-    if (approxSurface) {
-      approxSurface.addFace(face);
+    const stitchedSurface = face.data[FACE_CHUNK];
+    if (stitchedSurface) {
+      stitchedSurface.addFace(face);
     }
   }
   for (let e of shell.edges) {
     const face1 = e.halfEdge1.loop.face;
     const face2 = e.halfEdge2.loop.face;
-    const approxSurface1 = face1.data[FACE_CHUNK];
-    const approxSurface2 = face2.data[FACE_CHUNK];
-    if (approxSurface1 !== undefined && approxSurface1 === approxSurface2) {
-      e.data[EDGE_AUX] = approxSurface1;
-    } else if (approxSurface1 !== undefined || approxSurface2 !== undefined ) {
-      const o1 = approxSurface1 !== undefined ? approxSurface1 : face1.surface;
-      const o2 = approxSurface2 !== undefined ? approxSurface2 : face2.surface;
-      const approxCurve = getCurve(index, o1, o2);
-      approxCurve.addEdge(e);
+    const stitchedSurface1 = face1.data[FACE_CHUNK];
+    const stitchedSurface2 = face2.data[FACE_CHUNK];
+    if (stitchedSurface1 !== undefined && stitchedSurface1 === stitchedSurface2) {
+      e.data[EDGE_AUX] = stitchedSurface1;
+    } else if (stitchedSurface1 !== undefined || stitchedSurface2 !== undefined ) {
+      const o1 = stitchedSurface1 !== undefined ? stitchedSurface1 : face1.surface;
+      const o2 = stitchedSurface2 !== undefined ? stitchedSurface2 : face2.surface;
+      const stitchedCurve = getCurve(index, o1, o2);
+      stitchedCurve.addEdge(e);
     } 
   }
 }
@@ -77,7 +77,7 @@ export function update(shell) {
 export function getCurve(index, o1, o2) {
   let curve = index.get(o1, o2);
   if (curve == null) {
-    curve = new ApproxCurve(o1, o2);
+    curve = new StitchedCurve(o1, o2);
     index.set(o1, o2, curve);
   }
   return curve;