It's the common way to predigest the ellipse to four arcs in hand-drawing or construction lofting.

把椭圆线简化为四段圆弧，是手工作图或施工放样的常用方法。

youdao

It's the common way to predigest the ellipse to four arcs in hand-drawing or construction lofting.

把椭圆线简化为四段圆弧，是手工作图或施工放样的常用方法。

youdao