Fraunhofer IGD
Fraunhofer IGD
A new geometric and algorithmic method for the elimination of stair-step artefacts in multi-material 3D printing has been devised by scientists at the Fraunhofer Institute for Computer Graphics Research IGD in Darmstadt, Germany.
The research team has set out the findings in a paper which will be published to coincide with SIGGRAPH, a conference and exhibition on computer graphics and interactive techniques.
Stair-step artefacts are unavoidable in conventional 3D printing processes, being visually disturbing and sometimes structurally detrimental to the print. The process developed by researchers at the Fraunhofer Institute for PolyJet printers minimises quantisation errors, making stair-step artefacts no longer noticeable.
To avoid the quantisation errors, the surface is modulated with a high-frequency signal. This results in geometrically accurate and colour-true surfaces.
The modulation of the surface with a high-frequency signal, such as blue noise, leads to a distribution of quantisation errors to high frequencies, which are then removed by the function of the human eye and multiple printing processes.
Alan Brunton, a member of the three-person team who wrote the report, explained: “The printing time remains the same, regardless of the process. The dithering process does not require additional computing time either.”
The process is used in the entertainment industry, for figures and objects in animated movies, video games and board games. The items benefit from the geometric and colour precision that is part of the shape dithering approach and so they look especially realistic.
The solution presented in the paper by the Fraunhofer scientists was used with the Cuttlefish 3D printer driver that was developed by Fraunhofer IGD. The team plans to investigate the further hypothesis of whether the smoother surface that can now be achieved is also more resilient.
The Cuttlefish 3D printer driver became optimised with Stratasys PolyJet technology last summer when the major 3D printing manufacturer announced it would be supporting the institute with future software enhancements.
The paper, titled Shape Dithering for 3D Printing, has been accepted for presentation at SIGGRAPH 2022, a trade fair for computer graphics, and will be presented by Mostafa Morsy Abdelkader Morsy, the lead author.
The full paper can be found here.
