3D-Printed Tree Knothole Fillers for On-Demand Tree Reconstruction

Abstract

When trees grow, they can rotate or break by external forces, forming holes on the exterior. These holes are bad for aesthetics and significant factors in the quality drop of the trees. These problems should not be in trees like national natural monuments, and we should preserve these trees. Currently, the trees are treated by filling the holes site with polyurethane (PU) filler. However, this method is still not good for external recovery, especially for color and surface texture. In this study, we tried to reconstruct the external structure of the holes sites of the tree with 3D scanning and printing methods. 3D scanning was carried out to transfer the holes of a tree to a modeling program and reverse engineer the holes in the tree. The reverse-engineered fillers were 3D-printed with fused deposition modeling methods. The texture of 3D-printed fillers was significantly better than that of PU fillers. It was confirmed that the artificial bark skin made using reverse engineering technique is more similar in color and texture to the actual bark than the traditional artificial bark skin using urethane foam. The method was possible to realize more aesthetically tree-like surfaces compared with conventional methods.