diff --git a/web/app/sketcher/actions/constraintActions.js b/web/app/sketcher/actions/constraintActions.js
index 642d7312..7530b0cb 100644
--- a/web/app/sketcher/actions/constraintActions.js
+++ b/web/app/sketcher/actions/constraintActions.js
@@ -2,7 +2,7 @@ import {AlgNumConstraint, ConstraintDefinitions} from "../constr/ANConstraints";
 import {EndPoint} from "../shapes/point";
 import {Circle} from "../shapes/circle";
 import {Segment} from "../shapes/segment";
-import {matchAll, matchTypes, sortSelectionByType} from "./matchUtils";
+import {isInstanceOf, matchAll, matchTypes, sortSelectionByType} from "./matchUtils";
 import constraints from "../../../test/cases/constraints";
 
 export default [
@@ -18,11 +18,11 @@ export default [
       const [first, ...others] = viewer.selected;
       let pm = viewer.parametricManager;
       for (let obj of others) {
-        pm.algnNumSystem.addConstraint(
+        pm._add(
           new AlgNumConstraint(ConstraintDefinitions.PCoincident, [first, obj])
         );
       }
-      pm.refresh();
+      pm.commit();
     }
   },
 
@@ -39,8 +39,7 @@ export default [
       const constraint = new AlgNumConstraint(ConstraintDefinitions.TangentLC, [line, circle]);
       constraint.initConstants();
       const pm = viewer.parametricManager;
-      pm.algnNumSystem.addConstraint(constraint);
-      pm.refresh();
+      pm.add(constraint);
     }
 
   },
@@ -54,7 +53,7 @@ export default [
       const {viewer} = ctx;
       const [pt, line] = sortSelectionByType(viewer.selected);
       let pm = viewer.parametricManager;
-      pm.algnNumSystem.addConstraint(new AlgNumConstraint(ConstraintDefinitions.PointOnLine, [pt, line]));
+      pm.add(new AlgNumConstraint(ConstraintDefinitions.PointOnLine, [pt, line]));
     }
   },
 
@@ -73,11 +72,11 @@ export default [
 
       editConstraint(ctx, firstConstr, () => {
         const pm = viewer.parametricManager;
-        pm.algnNumSystem.addConstraint(firstConstr);
+        pm._add(firstConstr);
         for (let i = 1; i < viewer.selected.length; ++i) {
-          pm.algnNumSystem.addConstraint(new AlgNumConstraint(ConstraintDefinitions.Angle, [viewer.selected[i]], {...firstConstr.constants}));
+          pm._add(new AlgNumConstraint(ConstraintDefinitions.Angle, [viewer.selected[i]], {...firstConstr.constants}));
         }
-        pm.refresh();
+        pm.commit();
       });
     }
   },
@@ -97,12 +96,12 @@ export default [
 
       editConstraint(ctx, firstConstr, () => {
         const pm = viewer.parametricManager;
-        pm.algnNumSystem.addConstraint(firstConstr);
+        pm._add(firstConstr);
         for (let i = 2; i < viewer.selected.length; ++i) {
-          pm.algnNumSystem.addConstraint(new AlgNumConstraint(ConstraintDefinitions.Angle,
+          pm._add(new AlgNumConstraint(ConstraintDefinitions.Angle,
             [viewer.selected[i-1], viewer.selected[i]], {...firstConstr.constants}));
         }
-        pm.refresh();
+        pm.commit();
       });
     }
   },
@@ -122,11 +121,11 @@ export default [
 
       editConstraint(ctx, firstConstr, () => {
         const pm = viewer.parametricManager;
-        pm.algnNumSystem.addConstraint(firstConstr);
+        pm._add(firstConstr);
         for (let other of others) {
-          pm.algnNumSystem.addConstraint(new AlgNumConstraint(ConstraintDefinitions.SegmentLength, [other], {...firstConstr.constants}));
+          pm._add(new AlgNumConstraint(ConstraintDefinitions.SegmentLength, [other], {...firstConstr.constants}));
         }
-        pm.refresh();
+        pm.commit();
       });
     }
   },
@@ -143,7 +142,35 @@ export default [
 
       const constr = new AlgNumConstraint(ConstraintDefinitions.LockPoint, [point]);
       constr.initConstants();
-      editConstraint(ctx, constr, () => viewer.parametricManager.addAlgNum(constr));
+      editConstraint(ctx, constr, () => viewer.parametricManager.add(constr));
+    }
+  },
+
+  {
+    shortName: 'Mirror',
+    description: 'Mirror Objects',
+    selectionMatcher: selection => isInstanceOf(selection[0], Segment) && selection.length > 1,
+
+
+    invoke: ctx => {
+      const {viewer} = ctx;
+
+      const objects = viewer.selected;
+      const managedObjects = [];
+      for (let i = 1; i < objects.length; i++) {
+        let obj = objects[i];
+        const copy = obj.copy();
+        obj.layer.add(copy);
+        managedObjects.push(copy);
+      }
+
+      ConstraintDefinitions.Mirror.modify(objects, managedObjects);
+
+
+      // const constr = new AlgNumConstraint(ConstraintDefinitions.Mirror, [...objects, ...managedObjects]);
+
+      // viewer.parametricManager.addModifier(constr);
+
     }
   }
 
diff --git a/web/app/sketcher/actions/generatorActions.js b/web/app/sketcher/actions/generatorActions.js
new file mode 100644
index 00000000..a61b7185
--- /dev/null
+++ b/web/app/sketcher/actions/generatorActions.js
@@ -0,0 +1,19 @@
+import {isInstanceOf} from "./matchUtils";
+import {Generator} from "../id-generator";
+
+export default [
+
+
+  {
+    shortName: 'Mirror',
+    description: 'Mirror Objects',
+    selectionMatcher: selection => isInstanceOf(selection[0]) && selection.length > 1,
+
+    invoke: ctx => {
+      const {viewer} = ctx;
+      viewer.parametricManager.addGenerator(new Generator(GeneratorDefinitions.Mirror, [...viewer.selected]));
+    }
+  },
+
+];
+
diff --git a/web/app/sketcher/actions/matchUtils.js b/web/app/sketcher/actions/matchUtils.js
index 57fc2d3e..7cd8d0f4 100644
--- a/web/app/sketcher/actions/matchUtils.js
+++ b/web/app/sketcher/actions/matchUtils.js
@@ -33,6 +33,10 @@ export function matchTypes(selection) {
   return si === selection.length && i === arguments.length;
 }
 
+export function isInstanceOf(obj, shapeConstructor) {
+  return obj._class === shapeConstructor.prototype._class;
+}
+
 export function sortSelectionByType(selection) {
   return [...selection].sort((a, b) => a._class.localeCompare(b._class))
 }
diff --git a/web/app/sketcher/components/ConstraintExplorer.jsx b/web/app/sketcher/components/ConstraintExplorer.jsx
index 8a813fa3..d637da9e 100644
--- a/web/app/sketcher/components/ConstraintExplorer.jsx
+++ b/web/app/sketcher/components/ConstraintExplorer.jsx
@@ -38,8 +38,8 @@ export function ConstraintList() {
 
 
   return constraints.map((c, i) => {
-    const conflicting = viewer.parametricManager.algnNumSystem.conflicting.has(c);
-    const redundant = viewer.parametricManager.algnNumSystem.redundant.has(c);
+    const conflicting = false; //viewer.parametricManager.algNumSystem.conflicting.has(c);
+    const redundant = false; //viewer.parametricManager.algNumSystem.redundant.has(c);
 
     return <div key={c.id} className={cx(ls.objectItem, conflicting&&ls.conflicting, redundant&&ls.redundant)}
          onClick={() => viewer.parametricManager.updateConstraintConstants(c)}
diff --git a/web/app/sketcher/constr/ANConstraints.js b/web/app/sketcher/constr/ANConstraints.js
index 3aaf9df1..912d3271 100644
--- a/web/app/sketcher/constr/ANConstraints.js
+++ b/web/app/sketcher/constr/ANConstraints.js
@@ -3,6 +3,8 @@ import {indexById} from "../../../../modules/gems/iterables";
 import {DEG_RAD, distanceAB} from "../../math/math";
 import {COS_FN, Polynomial, POW_1_FN, POW_2_FN, SIN_FN} from "./polynomial";
 import {Types} from "../io";
+import {Constraints} from "../constraints";
+import Vector from "../../../../modules/math/vector";
 
 export const ConstraintDefinitions = indexById([
 
@@ -273,6 +275,36 @@ export const ConstraintDefinitions = indexById([
       polynomials.push(new Polynomial(-x).monomial().term(px, POW_1_FN));
       polynomials.push(new Polynomial(-y).monomial().term(py, POW_1_FN));
     },
+  },
+
+
+  {
+    id: 'Mirror',
+    name: 'Mirror Objects',
+
+    modify: (referenceObjects, managedObjects) => {
+
+      const reflectionLine = referenceObjects[0];
+
+      const dir = new Vector();
+      dir.set(-(reflectionLine.b.y - reflectionLine.a.y), reflectionLine.b.x - reflectionLine.a.x, 0)._normalize();
+
+      for (let i = 0; i < managedObjects.length; i++) {
+        let origin = reflectionLine.a.toVector();
+
+        const pointMirroring = (x, y) => {
+          let pt = new Vector(x, y, 0);
+          let proj = dir.dot(pt.minus(origin));
+          return dir.multiply(- proj * 2)._plus(pt);
+        };
+
+        referenceObjects[i+1].mirror(managedObjects[i], pointMirroring);
+      }
+    },
+
+    referenceObjects: objects => objects.slice(0, (objects.length >> 1) + 1),
+    managedObjects: objects => objects.slice((objects.length + 1) >> 1)
+
   }
 
 ]);
@@ -289,8 +321,26 @@ export class AlgNumConstraint {
     this.internal = false;
     this.schema = schema;
     this.params = [];
-    this.schema.defineParamsScope(this.objects, p => this.params.push(p));
-    // this.paramSet = new Set(this.params);
+    if (this.schema.defineParamsScope) {
+      this.schema.defineParamsScope(this.objects, p => this.params.push(p));
+    }
+
+    this.modifier = this.schema.modify !== undefined;
+    if (this.modifier) {
+      this.referenceObjects = this.schema.referenceObjects(this.objects);
+      this.managedObjects = this.schema.managedObjects(this.objects);
+      this.managedObjects.forEach(o => {
+        if (o.managedBy) {
+          throw 'there can be only one managing modifier for an object';
+        }
+        o.managedBy = this;
+      });
+    }
+  }
+
+  modify() {
+    this.resolveConstants();
+    this.schema.modify(this.referenceObjects, this.managedObjects, this.resolvedConstants);
   }
 
   collectPolynomials(polynomials) {
diff --git a/web/app/sketcher/constr/AlgNumSystem.js b/web/app/sketcher/constr/AlgNumSystem.js
index b07b9325..8f108788 100644
--- a/web/app/sketcher/constr/AlgNumSystem.js
+++ b/web/app/sketcher/constr/AlgNumSystem.js
@@ -1,32 +1,18 @@
-import {createByConstraintName} from "./solverConstraints";
-import {Param, prepare} from "./solver";
-import {findConstructionCluster} from "./constructions";
-import {GCCircle, GCPoint} from "./constractibles";
-import {eqEps, eqTol} from "../../brep/geom/tolerance";
+import {prepare} from "./solver";
+import {eqEps} from "../../brep/geom/tolerance";
 import {Polynomial, POW_1_FN} from "./polynomial";
-import {compositeFn, NOOP} from "../../../../modules/gems/func";
-import {sq} from "../../math/math";
+import {compositeFn} from "gems/func";
 
 export class AlgNumSubSystem {
 
-
-  generator = NOOP;//new BoundaryObjectsGenerator();
+  modifiers = [];
 
   allConstraints = [];
 
-  ownParams = new Set();
-
-  readOnlyParams = new Set();
-
-  generatedParams = new Set();
-
   paramToIsolation = new Map();
 
   eliminatedParams = new Map();
 
-  // generators = [];
-  subSystems = []; //subsystems are generated by generators only
-
   polynomials = [];
   substitutedParams = [];
   polyToConstr = new Map();
@@ -36,9 +22,7 @@ export class AlgNumSubSystem {
 
   snapshot = new Map();
 
-
-  constructor(generator = NOOP) {
-    this.generator = generator;
+  constructor() {
 
     this.solveStatus = {
       error: 0,
@@ -47,7 +31,6 @@ export class AlgNumSubSystem {
 
   }
 
-
   get fullyConstrained() {
     return this.dof === 0;
   }
@@ -62,11 +45,6 @@ export class AlgNumSubSystem {
 
   addConstraint(constraint, _ancestorParams) {
 
-    if (this.canBeAdded(constraint.params)) {
-      // this.constraints.push(constraint);
-      // this.constraints
-    }
-
     this.makeSnapshot();
 
     this.allConstraints.push(constraint);
@@ -233,6 +211,8 @@ export class AlgNumSubSystem {
 
   prepare() {
 
+    this.isDirty = false;
+
     this.reset();
 
     this.evaluatePolynomials();
@@ -325,7 +305,9 @@ export class AlgNumSubSystem {
 
 
   solve(rough) {
-    this.generator();
+
+    // this.modifiers.forEach(m => m.modify());
+    // this.prepare();
 
     this.polynomialIsolations.forEach(iso => {
       iso.solve(rough);
@@ -381,17 +363,6 @@ export class AlgNumSubSystem {
     });
   }
 
-
-  canBeAdded(subjectParams, ancestorParams) {
-
-    for (let p of subjectParams) {
-      if (!this.ownParams.has(p) && (!ancestorParams || !ancestorParams.has(p))) {
-        return false;
-      }
-    }
-
-    return true;
-  }
 }
 
 
diff --git a/web/app/sketcher/io.js b/web/app/sketcher/io.js
index ccac5d90..91fee537 100644
--- a/web/app/sketcher/io.js
+++ b/web/app/sketcher/io.js
@@ -100,7 +100,7 @@ IO.prototype._loadSketch = function(sketch) {
       if (!!ioLayer.style) layer.style = ioLayer.style;
       layer.readOnly = !!ioLayer.readOnly;
       var layerData = ioLayer['data'];
-      for (i = 0; i < layerData.length; ++i) {
+      for (let i = 0; i < layerData.length; ++i) {
         var obj = layerData[i];
         var skobj = null;
         var _class = obj['_class'];
@@ -194,7 +194,7 @@ IO.prototype._loadSketch = function(sketch) {
     }
   }
 
-  for (i = 0; i < this.viewer.dimLayer.objects.length; ++i) {
+  for (let i = 0; i < this.viewer.dimLayer.objects.length; ++i) {
     obj = this.viewer.dimLayer.objects[i];
     if (obj._class === T.DIM || obj._class === T.HDIM || obj._class === T.VDIM) {
       obj.a = index[obj.a];
@@ -212,15 +212,14 @@ IO.prototype._loadSketch = function(sketch) {
     this.linkEndPoints(boundaryLayer.objects);
   }
 
-  var sketchConstraints = sketch['constraints'];
+  let sketchConstraints = sketch['constraints'];
   if (sketchConstraints !== undefined) {
-    for (var i = 0; i < sketchConstraints.length; ++i) {
+    for (let i = 0; i < sketchConstraints.length; ++i) {
       try {
         if (version > 1) {
-          this.viewer.parametricManager.algnNumSystem.addConstraint(AlgNumConstraint.read(sketchConstraints[i], index));
+          this.viewer.parametricManager._add(AlgNumConstraint.read(sketchConstraints[i], index));
         } else {
-          const c = this.parseConstr(sketchConstraints[i], index);
-          this.viewer.parametricManager._add(c);
+          console.error("old format - need an upgrade");
         }
       } catch (msg) {
         console.info("Skipping. " + msg);
@@ -228,7 +227,7 @@ IO.prototype._loadSketch = function(sketch) {
     }
     this.viewer.parametricManager.notify();
   }
-  var constants = sketch['constants'];
+  let constants = sketch['constants'];
   if (constants !== undefined) {
     this.viewer.params.constantDefinition = constants;
   }
@@ -333,10 +332,10 @@ IO.prototype.cleanUpData = function() {
   }
   this.viewer.deselectAll();
   Generator.resetIDGenerator(0);
-  if (this.viewer.parametricManager.algnNumSystem.allConstraints.length !== 0) {
-    this.viewer.parametricManager.reset();
-    this.viewer.parametricManager.notify();
-  }
+
+  this.viewer.parametricManager.reset();
+  this.viewer.parametricManager.notify();
+
 };
 
 IO.prototype._serializeSketch = function(metadata) {
@@ -400,7 +399,7 @@ IO.prototype._serializeSketch = function(metadata) {
   }
 
   sketch.constraints = [];
-  const systemConstraints = this.viewer.parametricManager.algnNumSystem.allConstraints;
+  const systemConstraints = this.viewer.parametricManager.allConstraints;
   for (let sc of systemConstraints) {
     if (!sc.internal) {
       sketch.constraints.push(sc.write());
diff --git a/web/app/sketcher/mirror.js b/web/app/sketcher/mirror.js
deleted file mode 100644
index 751cf2f1..00000000
--- a/web/app/sketcher/mirror.js
+++ /dev/null
@@ -1,16 +0,0 @@
-
-
-function mirrorManager() {
-  
-  let mirrors = [];
-  
-  function add() {
-    
-  }
-  
-  
-}
-
-function mirrorTool() {
-  
-}
\ No newline at end of file
diff --git a/web/app/sketcher/parametric.js b/web/app/sketcher/parametric.js
index d89f6b36..26e7fa8c 100644
--- a/web/app/sketcher/parametric.js
+++ b/web/app/sketcher/parametric.js
@@ -2,24 +2,30 @@ import {askNumber} from '../utils/utils';
 import {Constraints} from './constraints';
 import {AlgNumConstraint, ConstraintDefinitions} from "./constr/ANConstraints";
 import {AlgNumSubSystem} from "./constr/AlgNumSystem";
-import {stream} from "../../../modules/lstream";
+import {state, stream} from "../../../modules/lstream";
 
 export {Constraints, ParametricManager}
 
 class ParametricManager {
 
-  algnNumSystem;
   constantTable = {};
   externalConstantResolver = null;
 
-  $constraints = stream().remember([]);
+  solveSystems;
+
+  $update = stream();
+
+  $constraints = this.$update.map(layers => layers.reduce((all, layer) => {
+    layer.allConstraints.forEach(c => all.push(c));
+    layer.modifiers.forEach(c => all.push(c));
+    return all
+  }, []).sort((c1, c2) => c1.id - c2.id)).remember([]);
 
   constructor(viewer) {
     this.viewer = viewer;
 
     this.reset();
 
-
     this.viewer.params.define('constantDefinition', null);
     this.viewer.params.subscribe('constantDefinition', 'parametricManager', this.onConstantsExternalChange, this)();
     this.constantResolver = this.createConstantResolver();
@@ -27,12 +33,12 @@ class ParametricManager {
 
   }
 
-  reset() {
-    this.algnNumSystem = new AlgNumSubSystem();
+  get allConstraints() {
+    return this.$constraints.value;
   }
 
-  get subSystems() {
-    return this.system.subSystems;
+  reset() {
+    this.solveSystems = [new AlgNumSubSystem()];
   }
 
   addAlgNum(constr) {
@@ -81,7 +87,7 @@ class ParametricManager {
 
   onConstantsExternalChange(constantDefinition) {
     this.rebuildConstantTable(constantDefinition);
-    this.refresh();
+   // this.refresh();
   };
 
   defineNewConstant(name, value) {
@@ -111,24 +117,50 @@ class ParametricManager {
     this.viewer.parametricManager.refresh();
   };
 
-  notify(event) {
-    this.$constraints.next(this.algnNumSystem.allConstraints);
+  notify() {
+    this.$update.next(this.solveSystems);
   };
 
-  refresh() {
-    console.log("calling non existent method");
-  };
-
-  _add(constr) {
-    this.viewer.historyManager.checkpoint();
-    this.algnNumSystem.addConstraint(constr);
+  commit() {
     this.notify();
     this.viewer.refresh();
   };
 
+  getPlacementLayerIndex(objects) {
+    for (let i = this.solveSystems.length - 1; i >= 0; --i) {
+
+      const system = this.solveSystems[i];
+
+      for (let o of objects) {
+        if (o.solveSystem === system) {
+          return i;
+        }
+      }
+    }
+
+    return 0;
+  }
+
+  _add(constr) {
+
+    if (constr.modifier) {
+      throw 'use addModifier instead';
+    }
+
+    let system = this.solveSystems[this.getPlacementLayerIndex(constr.objects)];
+
+    for (let o of constr.objects) {
+      if (!o.solveSystem) {
+        o.solveSystem = system;
+      }
+    }
+
+    system.addConstraint(constr);
+  };
+
   add(constr) {
     this.viewer.historyManager.checkpoint();
-    this.algnNumSystem.addConstraint(constr);
+    this._add(constr);
     this.notify();
     this.viewer.refresh();
   };
@@ -136,7 +168,7 @@ class ParametricManager {
   addAll(constrs) {
     this.viewer.historyManager.checkpoint();
     for (let i = 0; i < constrs.length; i++) {
-      this.algnNumSystem.addConstraint(constrs[i]);
+      this._add(constrs[i]);
     }
     this.notify();
     this.viewer.refresh();
@@ -144,7 +176,7 @@ class ParametricManager {
 
   remove(constr) {
     this.viewer.historyManager.checkpoint();
-    this.algnNumSystem.removeConstraint(constr);
+    // this.algNumSystem.removeConstraint(constr);
     this.refresh();
   };
 
@@ -154,7 +186,7 @@ class ParametricManager {
     let toRemove = new Set();
 
     objects.forEach(obj => obj.visitParams(p => {
-      this.algnNumSystem.allConstraints.forEach(c => {
+      this.algNumSystem.allConstraints.forEach(c => {
         c.objects.forEach(o => {
 
         })
@@ -190,6 +222,34 @@ class ParametricManager {
       this.removeObjects(dependants);
     }
   };
+
+  prepare() {
+    this.solveSystems.forEach(system => system.prepare());
+  }
+
+  solve(rough) {
+    this.solveSystems.forEach(system => system.solve(rough));
+  }
+
+  addModifier(modifier) {
+
+    modifier.managedObjects.forEach(o => {
+      if (o.solveSystem) {
+        throw 'adding modifiers to already constrained objects isn not supported yet';
+      }
+    });
+
+    this.viewer.historyManager.checkpoint();
+    let index = this.getPlacementLayerIndex(modifier.referenceObjects) + 1;
+    if (index === this.solveSystems.length) {
+      this.solveSystems.push(new AlgNumSubSystem());
+    }
+    const solveSystem = this.solveSystems[index];
+    solveSystem.modifiers.push(modifier);
+
+    modifier.managedObjects.forEach(go => go.solveSystem = solveSystem);
+
+    this.notify();
+    this.viewer.refresh();
+  }
 }
-
-
diff --git a/web/app/sketcher/shapes/arc.js b/web/app/sketcher/shapes/arc.js
index ad164a7d..a9d1b69b 100644
--- a/web/app/sketcher/shapes/arc.js
+++ b/web/app/sketcher/shapes/arc.js
@@ -141,4 +141,3 @@ export class Arc extends SketchObject {
 }
 
 Arc.prototype._class = 'TCAD.TWO.Arc';
-Arc.prototype.TYPE = 'ARC';
\ No newline at end of file
diff --git a/web/app/sketcher/shapes/bezier-curve.js b/web/app/sketcher/shapes/bezier-curve.js
index b0a73e4f..6134ffc5 100644
--- a/web/app/sketcher/shapes/bezier-curve.js
+++ b/web/app/sketcher/shapes/bezier-curve.js
@@ -79,6 +79,5 @@ export class BezierCurve extends SketchObject {
   }
 }
 BezierCurve.prototype._class = 'TCAD.TWO.BezierCurve';
-BezierCurve.prototype.TYPE = 'BEZIER';
 
 const RECOVER_LENGTH = 100;
\ No newline at end of file
diff --git a/web/app/sketcher/shapes/circle.js b/web/app/sketcher/shapes/circle.js
index a4c1cd47..d26cdec0 100644
--- a/web/app/sketcher/shapes/circle.js
+++ b/web/app/sketcher/shapes/circle.js
@@ -38,7 +38,12 @@ export class Circle extends SketchObject {
   normalDistance(aim) {
     return Math.abs(math.distance(aim.x, aim.y, this.c.x, this.c.y) - this.r.get());
   }
+
+  copy() {
+    const circle = new Circle(this.c.copy());
+    circle.r.set(this.r.get());
+    return circle;
+  }
 }
 
 Circle.prototype._class = 'TCAD.TWO.Circle';
-Circle.prototype.TYPE = 'CIRCLE';
\ No newline at end of file
diff --git a/web/app/sketcher/shapes/ellipse.js b/web/app/sketcher/shapes/ellipse.js
index e2530411..a817ae19 100644
--- a/web/app/sketcher/shapes/ellipse.js
+++ b/web/app/sketcher/shapes/ellipse.js
@@ -93,7 +93,6 @@ export class Ellipse extends SketchObject {
   }
 }
 Ellipse.prototype._class = 'TCAD.TWO.Ellipse';
-Ellipse.prototype.TYPE = 'ELLIPSE';
 
 const sq = (a) => a * a;
 const RECOVER_LENGTH = 100;
\ No newline at end of file
diff --git a/web/app/sketcher/shapes/nurbsObject.js b/web/app/sketcher/shapes/nurbsObject.js
index ad24ee69..eac465bc 100644
--- a/web/app/sketcher/shapes/nurbsObject.js
+++ b/web/app/sketcher/shapes/nurbsObject.js
@@ -90,4 +90,3 @@ export class NurbsObject extends SketchObject {
 }
 
 NurbsObject.prototype._class = 'TCAD.TWO.NurbsObject';
-NurbsObject.prototype.TYPE = 'NURBS';
diff --git a/web/app/sketcher/shapes/point.js b/web/app/sketcher/shapes/point.js
index 761a2b02..ff6bcab7 100644
--- a/web/app/sketcher/shapes/point.js
+++ b/web/app/sketcher/shapes/point.js
@@ -83,5 +83,4 @@ export class EndPoint extends SketchObject {
 }
 
 EndPoint.prototype._class = 'TCAD.TWO.EndPoint';
-EndPoint.prototype.TYPE = 'POINT';
 
diff --git a/web/app/sketcher/shapes/segment.js b/web/app/sketcher/shapes/segment.js
index 1390a816..37104040 100644
--- a/web/app/sketcher/shapes/segment.js
+++ b/web/app/sketcher/shapes/segment.js
@@ -154,5 +154,3 @@ export class Segment extends SketchObject {
 }
 
 Segment.prototype._class = 'TCAD.TWO.Segment';
-
-Segment.prototype.TYPE = 'SEGMENT';
diff --git a/web/app/sketcher/shapes/sketch-object.js b/web/app/sketcher/shapes/sketch-object.js
index 7cf3a3c2..ea51f962 100644
--- a/web/app/sketcher/shapes/sketch-object.js
+++ b/web/app/sketcher/shapes/sketch-object.js
@@ -7,12 +7,13 @@ export class SketchObject extends Shape {
   constructor() {
     super();
     this.id = Generator.genID();
-    this.aux = false;
     this.marked = null;
     this.children = [];
     this.linked = [];
     this.layer = null;
     this.fullyConstrained = false;
+    this.managedBy = null;
+    this.solveSystem = null;
   }
 
   normalDistance(aim, scale) {
diff --git a/web/app/sketcher/tools/circle.js b/web/app/sketcher/tools/circle.js
index 8f609795..a6b4f80f 100644
--- a/web/app/sketcher/tools/circle.js
+++ b/web/app/sketcher/tools/circle.js
@@ -32,8 +32,8 @@ export class EditCircleTool extends Tool {
   }
 
   solveRequest(rough) {
-    this.solver = this.viewer.parametricManager.prepare([this.circle.r]);
-    this.solver.solve(rough, 1);
+    // this.viewer.parametricManager.prepare([this.circle.r]);
+    this.viewer.parametricManager.solve(rough);
   }
 
   mouseup(e) {
diff --git a/web/app/sketcher/tools/drag.js b/web/app/sketcher/tools/drag.js
index 2d9b253b..27d5d74d 100644
--- a/web/app/sketcher/tools/drag.js
+++ b/web/app/sketcher/tools/drag.js
@@ -25,7 +25,7 @@ export class DragTool extends Tool {
     this.obj.translate(dx, dy);
     (this.obj.parent || this.obj).syncGeometry();
     if (!Tool.dumbMode(e)) {
-      this.viewer.parametricManager.algnNumSystem.solve(true);
+      this.viewer.parametricManager.solve(true);
     }
     this.viewer.refresh();
   }
@@ -35,12 +35,12 @@ export class DragTool extends Tool {
     this.origin.y = e.offsetY;
     this.viewer.screenToModel2(e.offsetX, e.offsetY, this._point);
 
-    this.viewer.parametricManager.algnNumSystem.prepare();
+    this.viewer.parametricManager.prepare();
 
   }
 
   mouseup(e) {
-    this.viewer.parametricManager.algnNumSystem.solve(false);
+    this.viewer.parametricManager.solve(false);
     this.viewer.refresh();
     this.viewer.toolManager.releaseControl();
     var traveled = math.distance(this.origin.x, this.origin.y, e.offsetX, e.offsetY);