A technique to replicate the external and internal structures of wood using the Stratasys J750 Polyjet 3D printer was demonstrated by researchers at Columbia University, New York. The engineers were able to imitate the unique texture of olive wood via imaging and colour and voxel mapping techniques.
Recently, an MIT study showed how a 3D printer can reproduce classic works of art by using Artificial Intelligence. However, the issue was copying the colours, and merely the outer form of the painting.
However, another complication which surfaced in the study titled, Digital Wood: 3D Internal Color Texture Mapping, was replicating the internal texture of a wood block. The engineers dealt with an uphill task of seeing underneath the surface of the wood and replicating it using a 3D printer. Eventually, a destructive imaging technique, or destructive tomographic imaging, was utilised to expose and scan the internal structure. The process involved slicing the wood with a 3040T desktop CNC machine, with a camera controlled by a Python program taking consecutive images. Each slice cut away by the CNC machine was 27 microns in height corresponding to the layer height of the 3D printer. The CNC machine ran through the wooden surface 230 times, with the attached camera capturing a picture of the wood every time.
Thereafter, the images were processed step by step to make them into a 3D printable code compatible with the J750 3D printer, which is capable of printing various materials and colours. Firstly, the images were scaled to match the 3D printer’s xy resolution of 600 x 300 pixels per inch. Secondly, the RGB images captured with the help of the CNC machine and the camera were translated into CMYK colour standard, similar to the inks used in the 3D printer. Finally, a GrabCAD voxel file (GCVF) was generated and printed.
The study concludes that texture properties such as specularity are limited by the mixing mechanics of photoacrylates and the printer resolution. Nonetheless, the ability to replicate internal grains in colour proﬁles can be extended to replicating stiffness proﬁles for materials whose physical properties map closely to their visual properties. For designers and manufacturers, the ability to take the internal proﬁle of one material and apply it to another has signiﬁcant implications.