修改自定义编号判断

src/SimpleBoard.ts

@@ -154,7 +154,7 @@ export class SimpleBoard
         mesh.userData = ext.Normal;
         edges.forEach(e => e.userData = ext.Normal);
         // 自定义编号
-        if (this._CustomNumber && this._CustomNumber.length > 0)
+        if (this._CustomNumber)
         {
             mesh.add(this.createCustomNo());
         }