:: modelling


In a classical work flow, damage to the fragile charcoal surfaces on the torso of St. Luke would have been an unavoidable result, even in the case of a complex approach. Because the exact form of the connections had been acquired using 3D scanning, however, it was possible for the 3D lab of Deggendorf Institute of Technology to construct individual, passable building blocks based on the generated 3D models.


However, because of the amorphous shapes and charred connection points, the challenges involved in applying the replicated parts were very complex and required an individual solution for each attached element. In the 3D program, however, for all supplements the specific mounting could be planned precisely and prepared for later production.


Also wood-related conditions, such as the fiber direction of the wood, had to be considered. Likewise, the drillings and screw connections should already be precisely defined in virtual space. In some areas the additions hovered between the original fragments at minimal distances. In order to ensure the necessary statics, in this case additional auxiliary constructions were integrated in the interior of the figure, to which the attachments could be screwed.


Many forms were so complex that they could not be made in one piece, or could not be attached. For example, the entire supplement for the burned left side of the figure had to be subdivided into numerous individual elements in 3D modelling. Thus they could be one by one produced and attached to the torso.


In the case of particularly difficult parts, it was necessary to check the fit by means of 3D printing before the final production in wood. This happened, for example, with the extremely thin mask for the charred left face of the bull.


:: production

Like the original sculpture, all produced supplementary parts were also made of lime wood. The first step of production was milling on large CNC machines. After a carpenter had glued matching blocks of wooden planks, they were clamped in the mill and machined by rail, until milled parts for all the attachments had been produced.


However, some of the supplementary parts had such a complicated geometry that it would not have been possible to manufacture them in the CNC milling machine. In order to be able to clamp these workpieces in the machine nevertheless, special auxiliary constructions had to be attached to these geometries in the 3D software.


In case of the thin mask for the bull's cheek, a special negative mold had to be milled, to which the workpiece could be sucked by vacuum in order to be able to process both the front and the rear. Because this component had a wall thickness of less than one millimeter in some places, it was one of the biggest challenges in the manufacturing process. In order to prevent the wood from being destroyed during the production process, the bull's mask was the only element to be milled from the much tougher maple wood. In the end, the milling part was so thin that the light would shine through in some places.


Already during milling, blind holes and holes for mounting were also incorporated into the workpieces in order to allow the screws to disappear later in the course of the assembly under dowels. The ends of the dowels were finally cut to form a closed wooden surface.





:: sculpture

In spite of all the advantages of machine production, there were still numerous steps for the sculptor, which should be deliberately carried out by hand. After all, the quality of Balthasar Ableithner's early baroque sculpture had to be achieved not only in its artistic form, but also in the surface finish. For example, the milled parts were cut as required or smoothed with rasps in order to achieve a suitable structure and differentiation of the forms and to provide an optimal ground for a later white painting of the sculpture.


First, the milled parts came to the sculptor's studio, where they were freed from the superfluous milling aids and brought into their final form. In the case of complex, multi-part additions, parts were already pre-assembled in the workshop, so that everything was fitting as good as possible during the later mounting in the church.


After the surfaces of the milled parts were finished and carved, they were attached to the original. However, they were not glued on but fixed with screws. In this way, the goal of preserving the monument could be fulfilled. The supplements are reversible and the original substance was not damaged further. In addition, stainless steel screws have been used without exception to prevent potential corrosion and prevent tensions in the wood.


All the works on the sculpture of the Evangelist Luke in the Munich Theatine Church are documented in detail and clearly illustrated in the publication „Lukas aus der Asche – Auferstandenes Kulturerbe aus dem 3D-Labor“ (Luke from the Ashes - Risen Cultural Heritage from the 3D Lab).









3D model of supplements for the burned left side

Graphic: Deggendorf Institute of Technology

:: deutsch


The supplemented left side of Luke with book

Photograph: Deggendorf Institute of Technology

Supplemented bull face made of maple wood

Photograph: Deggendorf Institute of Technology

© 2017 Deggendorf Institute of Technology

© 2017 Deggendorf Institute of Technology

© 2017

© 2017 Deggendorf Institute of Technology