diff --git a/web/app/cad/craft/datum/create/createDatumOperation.js b/web/app/cad/craft/datum/create/createDatumOperation.js
index 7854aae5..e851f614 100644
--- a/web/app/cad/craft/datum/create/createDatumOperation.js
+++ b/web/app/cad/craft/datum/create/createDatumOperation.js
@@ -5,6 +5,7 @@ import DatumObject3D from '../datumObject';
 import * as SceneGraph from 'scene/sceneGraph';
 import CSys from '../../../../math/csys';
 import {MDatum} from '../../../model/mdatum';
+import {roundInteractiveInput} from '../../wizard/roundUtils';
 
 function updateCSys(csys, params, findFace) {
   csys.move(0, 0, 0);
@@ -37,17 +38,20 @@ function previewer(ctx, initialParams, updateParams) {
   datum3D.onMove = (begin, end, delta) => {
     updateParams(params => {
       
-      params.x = end.x;
-      params.y = end.y;
-      params.z = end.z;
+      let x = end.x;
+      let y = end.y;
+      let z = end.z;
       if (params.face) {
         let face = ctx.services.cadRegistry.findFace(params.face);
         if (face) {
-          params.x -= face.csys.origin.x;
-          params.y -= face.csys.origin.y;
-          params.z -= face.csys.origin.z;
+          x -= face.csys.origin.x;
+          y -= face.csys.origin.y;
+          z -= face.csys.origin.z;
         }
       }
+      params.x = roundInteractiveInput(x);
+      params.y = roundInteractiveInput(y);
+      params.z = roundInteractiveInput(z);
     })
   };
   
diff --git a/web/app/cad/craft/datum/datumObject.js b/web/app/cad/craft/datum/datumObject.js
index aa301828..b0e70390 100644
--- a/web/app/cad/craft/datum/datumObject.js
+++ b/web/app/cad/craft/datum/datumObject.js
@@ -113,6 +113,11 @@ export default class DatumObject3D extends Object3D {
 
       let delta = dir.multiply(u);
       this.csys.origin._plus(delta);
+      
+      if (e.shiftKey) {
+        roundVector(this.csys.origin);
+      }
+      
       this.viewer.requestRender();
 
       this.onMove(this.dragInfo.csysOrigin, this.csys.origin, delta);
@@ -136,7 +141,7 @@ export default class DatumObject3D extends Object3D {
 function addOnHoverBehaviour(handle, viewer) {
   handle.onMouseDown = function(e, hits, startDrag) {
     let datum = this.parent.parent.parent;
-    if (datum.freezeDraggin) {
+    if (datum.freezeDragging) {
       return;
     }
     startDrag(datum);
@@ -148,4 +153,10 @@ function addOnHoverBehaviour(handle, viewer) {
   handle.onMouseLeave = function() {
     viewer.setVisualProp(handle.material, 'visible', false);
   };
+}
+
+function roundVector(v) {
+  v.x = Math.round(v.x);
+  v.y = Math.round(v.y);
+  v.z = Math.round(v.z);
 }
\ No newline at end of file
diff --git a/web/app/cad/craft/datum/move/moveDatumOperation.js b/web/app/cad/craft/datum/move/moveDatumOperation.js
index a5af369b..13283f78 100644
--- a/web/app/cad/craft/datum/move/moveDatumOperation.js
+++ b/web/app/cad/craft/datum/move/moveDatumOperation.js
@@ -2,7 +2,7 @@ import schema from './moveDatumOpSchema';
 import {renderPoint} from 'renders';
 import {MDatum} from '../../../model/mdatum';
 import MoveDatumWizard from './MoveDatumWizard';
-import {NOOP} from 'gems/func';
+import {roundInteractiveInput} from '../../wizard/roundUtils';
 
 
 function move(params, {cadRegistry}) {
@@ -35,9 +35,9 @@ function previewer(ctx, initialParams, updateParams) {
   datum3D.beginOperation();
   datum3D.onMove = (begin, end, delta) => {
     updateParams(params => {
-      params.x = end.x - mDatum.csys.origin.x;
-      params.y = end.y - mDatum.csys.origin.y;
-      params.z = end.z - mDatum.csys.origin.z;
+      params.x = roundInteractiveInput(end.x - mDatum.csys.origin.x);
+      params.y = roundInteractiveInput(end.y - mDatum.csys.origin.y);
+      params.z = roundInteractiveInput(end.z - mDatum.csys.origin.z);
     })
   };
 
diff --git a/web/app/cad/craft/wizard/roundUtils.js b/web/app/cad/craft/wizard/roundUtils.js
new file mode 100644
index 00000000..baa609c3
--- /dev/null
+++ b/web/app/cad/craft/wizard/roundUtils.js
@@ -0,0 +1,4 @@
+
+export function roundInteractiveInput(num) {
+  return num.toFixed(3)
+}
\ No newline at end of file
diff --git a/web/app/cad/craft/wizard/wizardPlugin.js b/web/app/cad/craft/wizard/wizardPlugin.js
index cc20f470..9ae104d6 100644
--- a/web/app/cad/craft/wizard/wizardPlugin.js
+++ b/web/app/cad/craft/wizard/wizardPlugin.js
@@ -1,6 +1,7 @@
 import {stream, state} from 'lstream';
 import initializeBySchema from '../intializeBySchema';
 import {clone, EMPTY_OBJECT} from 'gems/objects';
+import materializeParams from '../materializeParams';
 
 export function activate(ctx) {
 
@@ -70,6 +71,24 @@ export function activate(ctx) {
     return request
   }).remember(EMPTY_OBJECT);
 
+  streams.wizard.materializedWorkingRequest = streams.wizard.workingRequest.map(req => {
+    if (req.type) {
+      let operation = ctx.services.operation.get(req.type);
+      let params = {};
+      let errors = [];
+      materializeParams(ctx.services, req.params, operation.schema, params, errors, []);
+      if (errors.length !== 0) {
+        console.log(errors);
+        return INVALID_REQUEST;
+      }
+      return {
+        type: req.type,
+        params
+      };
+    }
+    return EMPTY_OBJECT;
+  }).filter(r => r !== INVALID_REQUEST).remember();
+
   services.wizard = {
 
     open: (type, initialOverrides) => {
@@ -99,3 +118,5 @@ export function activate(ctx) {
 function applyOverrides(params, initialOverrides) {
   Object.assign(params, initialOverrides);
 }
+
+const INVALID_REQUEST = {};
\ No newline at end of file
diff --git a/web/app/cad/preview/previewPlugin.js b/web/app/cad/preview/previewPlugin.js
index 73f8a3c7..78344a8a 100644
--- a/web/app/cad/preview/previewPlugin.js
+++ b/web/app/cad/preview/previewPlugin.js
@@ -10,7 +10,7 @@ export function activate(ctx) {
     previewer: null
   };
 
-  streams.wizard.workingRequest.attach(({type, params}) => {
+  streams.wizard.materializedWorkingRequest.attach(({type, params}) => {
     if (!type) {
       if (previewContext.previewer) {
         previewContext.previewer.dispose();