Replication of coloured 3D models simplified

The technique’s core is based on an accurate simulation of the thermoforming process, which ETH doctoral student Christian Schüller developed in the Interactive Geometry Lab under the supervision of ETH Professor Olga Sorkine-Hornung. The simulation computes an image from the coloured surface of a digital 3D model, which is then printed on to a plastic sheet. Through thermoforming, this sheet is then heated and forced into a three-dimensional shape. The key lies in computing the deformed image, so that the colours and patterns align perfectly with the geometric details of the mould.

The thermoforming technique is widespread in industrial applications and is used to manufacture many of the moulded parts that we use daily, such as yoghurt containers, inserts for boxes of chocolate and other packaging materials. “But the industrial method is not suitable for inexpensive manufacture of small batches or even individual pieces of complex shape or colour-printed models,” says Schüller. In order to print these parts accurately, specialist equipment and elaborate calibration are required.

The researchers have thus developed a method based on readily accessible and inexpensive equipment and materials, and which does not require highly specialised expertise.