Most 3D-printed objects currently come in a variety of exciting monochromatic colors. You've got red, white, blue and, if you're really lucky, a mix of two colors. And while the objects may have a great deal of detail, the surface will be bland.

　　现在大多数3D打印成品都是各种各样的单色。有红的，白的，蓝的，如果运气好，还有双色的。虽然成品能体现各种各样的细节，但是表面仍然没有做到栩栩如生。

　　Now, researchers have found a way to precisely affix complex coloring to objects, making them look somewhat photo-real (and perhaps a bit creepy).

　　现在，研究者们找到了一种可以对打印成品精准上色的方法。这种方法能够使得上色对象看起来活灵活现(也许看起来还有点毛骨悚然)。

　　The method, developed by a pair of teams at Zhejiang University and Columbia University, is called computational hydrographic printing. Hydrographic printing is not new; mass manufacturers use it to add repeating patterns to cheaply manufactured objects. It involves a vat of water and thin, pre-printed film, which is sprayed with a softening agent. The object is lowered into water and presses against the film, which stretches to wrap itself around every contour of the object. When the object is removed, it looks as if the pattern was part of the 3D-printing process.

　　这项技术由浙江大学和哥伦比亚大学的研究小组开发，称为“计算机水纹印刷”。水纹印刷并非是一项新技术。已经有许多制造商利用水纹印刷对廉价成品进行重复花纹的上色。整个过程需要在水槽中完成，上面有预制好的胶片，胶片上面喷印了一层柔软的试剂。需要着色的物体之后慢慢浸入水中，对着胶片按压，使得胶片能够完全包裹物体。

　　According to researchers, it's nearly impossible to precisely match the object with the film, hence why they usually use repeating patterns — so no one would notice if anything is out of alignment.

　　研究者表示，胶片要和待着色物体完全吻合是不太可能的，这也是制造商都使用重复花纹的原因——这样如果有什么地方没合上，也没人会发现。

　　The researchers realized that if they could use the 3D scan of the original object and pre-dip it into a simulated bucket of water and thin-printed film, they could figure out how to position and align more complex prints with objects. However, that simulation can't be run without first using a modified hydrographic printing rig, which is comprised of a vertical, motorized aluminum arm and gripper that moves up and down at 5mm per second, along with a Microsoft Kinect 3D image mapping device.

　　研究者认识到，如果能获取原始对象的3D扫描件，然后事先浸入一个模拟的水箱和薄型胶片，那么他们便可以知道如何把复杂的图案贴合物体。但是，这种模拟如果不改良现有的水纹打印装置，是无法运行的。改良后的水纹打印装置的构成是这样的：有一只垂直的铝制电动臂，还要有一个每秒上下活动5毫米的爪子，同事还要搭配Microsoft Kinect 3D成像设备。