In the Ruby API you get a reference to an entity and invoke its erase method. Without knowing the structure of your model I can’t give a Ruby snippet to get such a reference, as it would require knowing information such as what sort of entity is involved and what contains it.
创建阴影曲线，然后用套索选择进行删除，也是可以的。
It is also possible to create a shadow curve and then delete it with a lasso selection.