设置默认的返回值.

src/DatabaseServices/Curve.ts

@@ -25,11 +25,11 @@ export abstract class Curve extends Entity
     get StartParam(): number { return; }
     get EndPoint(): Vector3 { return; }
     get EndParam(): number { return; }
-    get Area(): number { return; }
+    get Area(): number { return 0; }
     //获得曲线的面积,逆时针为正,顺时针为负.
-    get Area2(): number { return; }
+    get Area2(): number { return 0; }
-    get Length(): number { return; }
+    get Length(): number { return 0; }
-    get IsClose(): boolean { return; }
+    get IsClose(): boolean { return false; }
     //曲线为顺时针
     get IsClockWise(): boolean { return this.Area2 < 0; }