Section: New Results

Colored 3D Printing

Participants : Sylvain Lefebvre, Jonàs Martínez Bayona, Noémie Vennin, Pierre Bedell.

In 2018 we kept developing our project regarding colored FDM printing. We have a paper accepted with minor revisions in ACM Transactions on Graphics. This was a joint work with Haichuan Song, then a post-doctoral researcher in ALICE. We worked on revising and refining our initial results throughout the year.

We proposed a novel algorithm for the problem of determining micro-layer mixtures to reproduce a subspace of material mixing ratios. We express the problem as fitting a simplex of minimal volume enclosing a set of points. The vertices of the simplex correspond to micro-layer mixtures, while the point set captures the desired mixtures within the model. This algorithm replaces the previous non-linear, gradient based optimizer. It achieves better results at a fraction of the previous computation time.

We also developed, through the internship of Pierre Bedell, a 3D printer able to mix up to five filaments. We ran extensive testing and implemented additional improvements regarding flow control during deposition. Pierre Bedell joined the team as a research engineer and will keep participating in this project.

Noémie Vennin joined the team on a funding from Université de Lorraine to explore material aspects of the project, in a close collaboration with Sandrine Hoppe (LRGP). This part of the project receives support from the CPER Cyber-entreprise, thanks to which we acquired equipment to develop our own filament formulations, mixing pigments and additives to control color and transparency. Pierre Bedell and Noémie Vennin are developing a calibration process to determine the achievable color space given specific filaments, but also to tackle the inverse problem of designing filaments spanning a desired color space.