diff --git a/web/app/3d/modeler-app.js b/web/app/3d/modeler-app.js
index 69b8cc2e..2d6a86cc 100644
--- a/web/app/3d/modeler-app.js
+++ b/web/app/3d/modeler-app.js
@@ -16,6 +16,9 @@ import {AddDebugSupport} from './debug'
 import {init as initSample} from './sample'
 import '../../css/app3d.less'
 
+import * as BREPBuilder from '../brep/brep-builder'
+import {SceneSolid} from '../brep/viz/scene-solid'
+
 function App() {
   this.id = this.processHints();
   this.bus = new Bus();
@@ -63,8 +66,23 @@ function App() {
     }
     app._refreshSketches();
   });
+  this.BREPTest();
 }
 
+App.prototype.BREPTest = function() {
+
+  const box = BREPBuilder.createPrism([
+    BREPBuilder.point(-250, -250, 250),
+    BREPBuilder.point(250, -250, 250),
+    BREPBuilder.point(250, 250, 250),
+    BREPBuilder.point(-250, 250, 250),
+  ], 500);
+  
+  const sceneSolid = new SceneSolid(box);
+  this.viewer.workGroup.add(sceneSolid.cadGroup);
+  this.viewer.render()
+};
+
 App.prototype.processHints = function() {
   let id = window.location.hash.substring(1);
   if (!id) {
diff --git a/web/app/brep/brep-builder.js b/web/app/brep/brep-builder.js
new file mode 100644
index 00000000..9be57462
--- /dev/null
+++ b/web/app/brep/brep-builder.js
@@ -0,0 +1,99 @@
+import {Shell} from './topo/shell'
+import {Vertex} from './topo/vertex'
+import {Loop} from './topo/loop'
+import {Face} from './topo/face'
+import {HalfEdge, Edge} from './topo/edge'
+import {Line} from './geom/impl/line'
+import {Plane} from './geom/impl/plane'
+import {Point} from './geom/point'
+import * as cad_utils from '../3d/cad-utils'
+
+
+export function createPrism(basePoints, height) {
+  const normal = cad_utils.normalOfCCWSeq(basePoints);
+  const baseLoop = createPlaneLoop(basePoints.map(p => new Vertex(p)));
+  const baseFace = createPlaneFace(normal, baseLoop);
+
+  const lidNormal = normal.multiply(-1);
+  const offVector = lidNormal.multiply(height);
+  const lidPoints = basePoints.map(p => p.plus(offVector));
+  const lidLoop = createPlaneLoop(lidPoints.map(p => new Vertex(p)));
+  const lidFace = createPlaneFace(lidNormal, lidLoop);
+
+  const shell = new Shell();
+  
+  for (let i = 0; i < baseLoop.halfEdges.length; i++) {
+    const baseHalfEdge = baseLoop.halfEdges[i];
+    const lidHalfEdge = lidLoop.halfEdges[i];
+    const wallLoop = createPlaneLoop([baseHalfEdge.vertexA, baseHalfEdge.vertexB, lidHalfEdge.vertexB, lidHalfEdge.vertexA]);
+
+    const baseEdge = new Edge(new Line());
+    linkHalfEdges(baseEdge, baseHalfEdge, wallLoop.halfEdges[0]);
+    
+    const lidEdge = new Edge(new Line());
+    linkHalfEdges(lidEdge, lidHalfEdge, wallLoop.halfEdges[2]);
+
+    const wallNormal = cad_utils.normalOfCCWSeq([baseHalfEdge.vertexA.point, baseHalfEdge.vertexB.point, lidHalfEdge.vertexB.point]);
+    
+    const wallFace = createPlaneFace(wallNormal, wallLoop);
+
+    shell.faces.push(wallFace);
+  }
+  
+  iterateSegments(shell.faces, (a, b) => {
+    linkHalfEdges(new Edge(new Line()), a.outerLoop.halfEdges[1], b.outerLoop.halfEdges[3]);
+  });
+  shell.faces.push(baseFace, lidFace);
+  return shell;
+}
+
+function createPlaneFace(normal, loop) {
+  const w = loop.halfEdges[0].vertexA.point.dot(normal);
+  const plane = new Plane(normal, w);
+  const face = new Face(plane);
+  face.outerLoop = loop;
+  return face;
+}
+
+
+export function linkHalfEdges(edge, halfEdge1, halfEdge2) {
+  halfEdge1.edge = edge;
+  halfEdge2.edge = edge;
+  edge.halfEdge1 = halfEdge1;
+  edge.halfEdge2 = halfEdge2;
+  halfEdge1.vertexA.edges.push(edge);
+  halfEdge1.vertexB.edges.push(edge);
+}
+
+export function createPlaneLoop(vertices) {
+  
+  const loop = new Loop();
+  
+  iterateSegments(vertices, (a, b) => {
+    const halfEdge = new HalfEdge();
+    halfEdge.loop = loop;
+    halfEdge.vertexA = a;
+    halfEdge.vertexB = b;
+    loop.halfEdges.push(halfEdge);
+  });
+
+  iterateSegments(loop.halfEdges, (prev, next) => {
+    prev.next = next;
+    next.prev = prev;
+  });
+  
+  return loop;
+}
+
+export function point(x, y, z) {
+  return new Point(x, y, z);
+}
+
+export function iterateSegments(items, callback) {
+  let length = items.length;
+  for (let i = 0; i < length; i++) {
+    let j = (i + 1) % length;
+    callback(items[i], items[j], i, j);
+  }
+}
+
diff --git a/web/app/brep/geom/curve.js b/web/app/brep/geom/curve.js
new file mode 100644
index 00000000..a39cfb17
--- /dev/null
+++ b/web/app/brep/geom/curve.js
@@ -0,0 +1,8 @@
+
+export class Curve {
+
+  constructor() {
+
+  }
+
+}
\ No newline at end of file
diff --git a/web/app/brep/geom/impl/line.js b/web/app/brep/geom/impl/line.js
new file mode 100644
index 00000000..c1438727
--- /dev/null
+++ b/web/app/brep/geom/impl/line.js
@@ -0,0 +1,9 @@
+import {Curve} from '../curve'
+
+export class Line extends Curve {
+
+  constructor() {
+    super();
+  }
+
+}
\ No newline at end of file
diff --git a/web/app/brep/geom/impl/plane.js b/web/app/brep/geom/impl/plane.js
new file mode 100644
index 00000000..214131a6
--- /dev/null
+++ b/web/app/brep/geom/impl/plane.js
@@ -0,0 +1,24 @@
+import {Surface} from '../surface'
+import {AXIS} from  '../../../math/l3space'
+ 
+export class Plane extends Surface {
+
+  constructor(normal, w) {
+    super();
+    this.normal = normal;
+    this.w = w;
+  }
+
+  calculateBasis() {
+    const normal = this.normal;
+    let alignPlane, x, y;
+    if (Math.abs(normal.dot(AXIS.Y)) < 0.5) {
+      alignPlane = normal.cross(AXIS.Y);
+    } else {
+      alignPlane = normal.cross(AXIS.Z);
+    }
+    y = alignPlane.cross(normal);
+    x = y.cross(normal);
+    return [x, y, normal];
+  }
+}
\ No newline at end of file
diff --git a/web/app/brep/geom/point.js b/web/app/brep/geom/point.js
new file mode 100644
index 00000000..b05c851b
--- /dev/null
+++ b/web/app/brep/geom/point.js
@@ -0,0 +1,3 @@
+import Vector from '../../math/vector'
+
+export const Point = Vector;
\ No newline at end of file
diff --git a/web/app/brep/geom/surface.js b/web/app/brep/geom/surface.js
new file mode 100644
index 00000000..423675f6
--- /dev/null
+++ b/web/app/brep/geom/surface.js
@@ -0,0 +1,8 @@
+
+export class Surface {
+
+  constructor() {
+    
+  }
+
+}
\ No newline at end of file
diff --git a/web/app/brep/topo/Edge.js b/web/app/brep/topo/Edge.js
new file mode 100644
index 00000000..cc4796ba
--- /dev/null
+++ b/web/app/brep/topo/Edge.js
@@ -0,0 +1,26 @@
+
+export class Edge {
+
+  constructor(curve) {
+    this.curve = curve;
+    this.halfEdge1 = null;
+    this.halfEdge2 = null;
+  }
+}
+
+export class HalfEdge {
+
+  constructor() {
+    this.edge = null;
+    this.vertexA = null;
+    this.vertexB = null;
+    this.loop = null;
+    this.next = null;
+    this.prev = null;
+  }
+  
+  twin() {
+    return this.edge.halfEdge1 == this ? this.edge.halfEdge2 : this.edge.halfEdge1;
+  }
+  
+}
\ No newline at end of file
diff --git a/web/app/brep/topo/face.js b/web/app/brep/topo/face.js
new file mode 100644
index 00000000..db4a6079
--- /dev/null
+++ b/web/app/brep/topo/face.js
@@ -0,0 +1,10 @@
+
+export class Face {
+
+  constructor(surface) {
+    this.surface = surface;
+    this.outerLoop = null;
+    this.innerLoops = [];
+  }
+
+}
\ No newline at end of file
diff --git a/web/app/brep/topo/loop.js b/web/app/brep/topo/loop.js
new file mode 100644
index 00000000..8ae71af1
--- /dev/null
+++ b/web/app/brep/topo/loop.js
@@ -0,0 +1,12 @@
+
+export class Loop {
+
+  constructor() {
+    this.face = null;
+    this.halfEdges = [];
+  }
+
+  asPolygon() {
+    return this.halfEdges.map(e => e.vertexA.point);
+  }
+}
\ No newline at end of file
diff --git a/web/app/brep/topo/shell.js b/web/app/brep/topo/shell.js
new file mode 100644
index 00000000..72fceda5
--- /dev/null
+++ b/web/app/brep/topo/shell.js
@@ -0,0 +1,8 @@
+
+export class Shell {
+
+  constructor() {
+    this.faces = []
+  }
+
+}
\ No newline at end of file
diff --git a/web/app/brep/topo/vertex.js b/web/app/brep/topo/vertex.js
new file mode 100644
index 00000000..b1dda347
--- /dev/null
+++ b/web/app/brep/topo/vertex.js
@@ -0,0 +1,9 @@
+
+export class Vertex {
+  
+  constructor(point) {
+    this.point = point;
+    this.edges = [];
+  }
+  
+}
\ No newline at end of file
diff --git a/web/app/brep/viz/scene-solid.js b/web/app/brep/viz/scene-solid.js
new file mode 100644
index 00000000..110919fe
--- /dev/null
+++ b/web/app/brep/viz/scene-solid.js
@@ -0,0 +1,135 @@
+import Vector from '../../math/vector'
+import {Triangulate} from '../../3d/triangulation'
+
+export class SceneSolid {
+  
+  constructor(shell) {
+    this.shell = shell;
+
+    this.cadGroup = new THREE.Object3D();
+    this.cadGroup.__tcad_solid = this;
+    this.wireframeGroup = new THREE.Object3D();
+    this.cadGroup.add(this.wireframeGroup);
+
+    const geometry = new THREE.Geometry();
+    geometry.dynamic = true;
+    this.mesh = new THREE.Mesh(geometry, createSolidMaterial());
+    this.cadGroup.add(this.mesh);
+
+    this.polyFaces = [];
+    this.createFaces();
+    this.createEdges();
+    this.createVertices();
+  }
+  
+  createFaces() {
+    let off = 0;
+    let gIdx = 0;
+    const geom = this.mesh.geometry;
+    for (let brepFace of this.shell.faces) {
+      const polyFace = new SceneFace(brepFace);
+      this.polyFaces.push(polyFace);
+      const polygons = triangulate(brepFace);
+      for (let p = 0; p < polygons.length; ++p) {
+        const poly = polygons[p];
+        const vLength = poly.length;
+        if (vLength < 3) continue;
+        const firstVertex = poly[0];
+        geom.vertices.push(threeV(firstVertex));
+        geom.vertices.push(threeV(poly[1]));
+        const normal = threeV(brepFace.surface.normal);
+        for (let i = 2; i < vLength; i++) {
+          geom.vertices.push(threeV(poly[i]));
+
+          const a = off;
+          const b = i - 1 + off;
+          const c = i + off;
+          const face = new THREE.Face3(a, b, c);
+          polyFace.faces.push(face);
+          face.__TCAD_polyFace = polyFace;
+          face.normal = normal;
+          face.materialIndex = gIdx ++;
+          geom.faces.push(face);
+          //face.color.set(new THREE.Color().setRGB( Math.random(), Math.random(), Math.random()));
+        }
+        //view.setFaceColor(polyFace, utils.isSmoothPiece(group.shared) ? 0xFF0000 : null);
+        off = geom.vertices.length;
+      }
+    }
+    geom.mergeVertices();    
+  }
+
+  createEdges() {
+    const visited = new Set();
+    for (let face of this.shell.faces) {
+      for (let halfEdge of face.outerLoop.halfEdges) {
+        if (!visited.has(halfEdge.edge)) {
+          visited.add(halfEdge.edge);
+          this.addLineToScene(halfEdge.vertexA.point, halfEdge.vertexB.point, halfEdge.edge);
+        }  
+      }
+    }
+  }
+  
+  createVertices() {
+    
+  }
+
+  addLineToScene(a, b, edge) {
+    const  lg = new THREE.Geometry();
+    lg.vertices.push(a);
+    lg.vertices.push(b);
+    const line = new THREE.Line(lg, WIREFRAME_MATERIAL);
+    line.__TCAD_edge = edge;
+    this.wireframeGroup.add(line);
+  };
+
+}
+
+const WIREFRAME_MATERIAL = new THREE.LineBasicMaterial({color: 0xff0000, linewidth: 10});
+
+  
+class SceneFace {
+  constructor(brepFace) {
+    this.brepFace = brepFace;
+    this.faces = [];
+  }
+}
+
+function triangulate(face) {
+  function csgVert(data) {
+    return new Vector(data[0], data[1], data[2]);
+  }
+  function data(v) {
+    return [v.x, v.y, v.z];
+  }
+
+  var triangled = [];
+  const polygons = [face.outerLoop.asPolygon()];
+  for (let poly of polygons) {
+    let vertices = Triangulate([poly.map(v => data(v))], data(face.surface.normal));
+    for (let i = 0;  i < vertices.length; i += 3 ) {
+      var a = csgVert(vertices[i]);
+      var b = csgVert(vertices[i + 1]);
+      var c = csgVert(vertices[i + 2]);
+      triangled.push([a, b, c]);
+    }
+  }
+  return triangled;
+
+}
+
+
+function createSolidMaterial() {
+  return new THREE.MeshPhongMaterial({
+    vertexColors: THREE.FaceColors,
+    color: 0xB0C4DE,
+    shininess: 0,
+    polygonOffset : true,
+    polygonOffsetFactor : 1,
+    polygonOffsetUnits : 2,
+    side : THREE.DoubleSide
+  });
+}
+
+function threeV(v) {return new THREE.Vector3( v.x, v.y, v.z )}