该模型无需直接打印，用于在其他模型开孔，方便制作成挂饰钥匙扣等。

相比直接在模型上增加圆环，它更具有以下优势

  ① 不会突出表面，更美观。

  ② 打印时几乎不需要支撑。

  ③ 打印走线与模型融为一体，强度更高。

  ④ 通用于各种曲面、平面开孔。

使用方法简单，可直接下载后拖入拓竹切片软件，与需要开孔的模型组合后，使用布尔功能完成开孔。

This model does not require direct printing and is used for drilling holes in other models, making it easy to make into decorative keychains, etc.

Compared to directly adding circles to the model, it has the following advantages

① Will not protrude from the surface, more aesthetically pleasing.

② Printing requires almost no support.

③ The printing wiring is integrated with the model for higher strength.

④ Commonly used for opening holes on various surfaces and planes.

The usage method is simple. You can directly download and drag it into the bamboo slicing software, combine it with the model that needs to be drilled, and use Boolean function to complete the drilling.