But in recent years , various rapid - prototyping techniques that automatically produce three - dimensional parts from computer - aided - design data have reduced the time from weeks to days or hours 但近几年来,出现了很多可依据电脑辅助设计资料,自动制作立体模型的快速原型制作技术,将数星期的制作时间缩短到数天或几小时。