Draft (engineering)
（重定向自Draft angle）
In engineering, draft is the amount of taper for molded or cast parts perpendicular to the parting line. It can be measured in degrees or mm/mm (in/in).
Consider the fabrication of a hollow plastic box, without lid. Once the plastic has hardened around the mold, the mold must be removed. As the plastic hardens, it may contract slightly. By tapering the sides of the mold by an appropriate "draft angle", the mold will be easier to remove.