diff --git a/__test__/quokka.test.ts b/__test__/quokka.test.ts
new file mode 100644
index 000000000..dde52f0ce
--- /dev/null
+++ b/__test__/quokka.test.ts
@@ -0,0 +1,67 @@
+import * as THREE from 'three';
+
+import { GeUtils } from "../src/Geometry/GeUtils"
+
+let v = new THREE.Vector3(1, 0, 0);
+
+let v2 = new THREE.Vector3(1, 0.1, 0)
+
+
+let an = v.angleTo(v2);
+
+console.log('an: ', an);
+
+
+
+console.log(an);
+
+console.log(v.angleTo(v2));
+
+console.log(Math.PI * 0.25);
+
+
+console.log(v);
+console.log(v2);
+
+console.log(v.dot(v2));
+
+function fixAngle(an)
+{
+    let pi4 = Math.PI * 0.5;
+    let rem = an % pi4;
+    if (rem < 0.1)
+    {
+        an -= rem;
+    }
+    else
+    {
+        an += 0.2;
+        rem = an % pi4;
+        if (rem < 0.1)
+        {
+            an -= rem;
+        }
+        else
+        {
+            an -= 0.2
+        }
+    }
+    return an;
+}
+
+an = fixAngle(an);
+
+console.log(an);
+
+GeUtils.angle(v, an, 1);
+
+console.log(v);
+
+console.log(fixAngle(Math.PI / 2 + 0.0));
+console.log(fixAngle(Math.PI / 2 + 0.05));
+
+console.log(Math.PI % Math.PI);
+
+
+
+console.log(fixAngle(Math.PI / 2 + 0.05) % Math.PI / 2);
diff --git a/src/Editor/Editor.ts b/src/Editor/Editor.ts
index 33d3509ea..78969043b 100644
--- a/src/Editor/Editor.ts
+++ b/src/Editor/Editor.ts
@@ -13,6 +13,7 @@ import { KeyBoardControls } from './KeyBoardControls';
 import { MouseControls } from './MouseControls';
 import { PromptPointResult, PromptStatus } from './PromptResult';
 import { SelectControls } from './SelectControls';
+import { GeUtils } from '../Geometry/GeUtils';
 
 //TODO: 增加鼠标状态. 鼠标位置.
 export class Editor
@@ -39,7 +40,7 @@ export class Editor
         this.m_InputState = InputState.GetPoint;
         let retValue = new PromptPointResult();
 
-        let removeSnap = this.Snap();
+        let removeSnap = this.Snap(prompt ? prompt.BasePoint : undefined);
         let res = new Promise<PromptPointResult>((resolve, reject) =>
         {
             let line: Line, removeDrag;
@@ -139,10 +140,57 @@ export class Editor
     }
 
     noSnapList = new Set<THREE.Object3D>();
-    Snap()
+    Snap(basePoint?: THREE.Vector3)
     {
         let testSnap = () =>
         {
+            if (basePoint)
+            {
+                function fixAngle(an)
+                {
+                    let pi2 = Math.PI * 0.5;
+                    let rem = an % pi2;
+                    if (rem < 0.1)
+                    {
+                        an -= rem;
+                    }
+                    else
+                    {
+                        an += 0.2;
+                        rem = an % pi2;
+                        if (rem < 0.1)
+                        {
+                            an -= rem;
+                        }
+                        else
+                        {
+                            an -= 0.2
+                        }
+                    }
+                    return an;
+                }
+                let p = this.m_MouseCtrl.m_CurMousePointWCS.clone().sub(basePoint);
+
+                let an = Math.atan2(p.y, p.x);
+                if (an < 0) an += Math.PI * 2;
+                an = fixAngle(an);
+                console.log('an: ', an);
+
+
+                if (an % (Math.PI * 0.5) < 0.01)
+                {
+
+                    let ptC = basePoint.clone();
+                    GeUtils.angle(ptC, an, basePoint.dot(this.m_MouseCtrl.m_CurMousePointWCS));
+
+
+                    app.m_Viewer.WorldToScreen(ptC);
+                    app.m_CursorViewer.SerCursorPostion(ptC);
+                    app.m_CursorViewer.render();
+                    return;
+                }
+            }
+
             for (let obj of app.m_Viewer.m_Scene.children)
             {
                 if (this.noSnapList.has(obj))
diff --git a/src/Editor/SelectControls.ts b/src/Editor/SelectControls.ts
index 684aa9ee3..e7cecc824 100644
--- a/src/Editor/SelectControls.ts
+++ b/src/Editor/SelectControls.ts
@@ -10,6 +10,7 @@ import { Editor } from './Editor';
 import { SelectBox } from './SelectBox';
 import { SelectPick } from './SelectPick';
 import { SelectSet, SelectType } from './SelectSet';
+import { commandMachine } from './CommandMachine';
 
 export class SelectControls
 {
@@ -88,6 +89,10 @@ export class SelectControls
 
         let snapEvent = () =>
         {
+            if (commandMachine.m_CommandIng)
+            {
+                return;
+            }
             for (let pts of app.m_Viewer.m_GripScene.children)
             {
                 if (pts instanceof THREE.Points)
diff --git a/src/Geometry/GeUtils.ts b/src/Geometry/GeUtils.ts
index a783c40b7..226eb8bef 100644
--- a/src/Geometry/GeUtils.ts
+++ b/src/Geometry/GeUtils.ts
@@ -17,6 +17,12 @@ export namespace GeUtils
         return v1.manhattanDistanceTo(v2) < 1e-8;
     }
 
+    export function angle(v: THREE.Vector3, an: number, dis: number)
+    {
+        v.x += Math.cos(an) * dis;
+        v.y += Math.sin(an) * dis;
+    }
+
     export function getLoocAtUpVec(dir: THREE.Vector3): THREE.Vector3
     {
         if (dir.equals(cZeroVec))