GALLERY

This project is a DeskProto application in sculpturing art. The Dutch artist Mrs. Eja Siepman van den Berg is famous for the perfectly refined human torso sculptures that she produces in white marble and other materials. As the completely manual production process of these sculptures requires much time, effort and hard labour she has been looking at new technologies to facilitate her work.

One of the possibilities is using CAD/CAM technology to create the final sculpture in stone, and thus to use an NC machine to perform most of the heavy labour. In this project the geometry again has been manually sculptured, however in plaster instead of in stone. The plaster sculpture has been digitized using a 3D laser scanner, and the resulting data have been used to create a 3D CAD-model.

An alternative approach would be to completely model the sculpture in 3D CAD. Expecting a number difficulties here it has been decided to start using a 3D laser scanner as input device.

DeskProto window showing the DXF-file (about 13,000 triangles)

In this project the DeskProto Rapid Prototyping software has been used to easily calculate NC milling paths for the CAD-geometry, and to create some scale-models in transparent perspex (being very fine sculptures themselves). The geometry has been transferred from the CAD-system using a DXF-file with a polyface mesh, the de-facto standard for presentation renderings.

DeskProto window showing part of the toolpaths (in order to make them clearly visible a larger path-distance has been used for this illustration)

As the models were created on a three-axis milling machine, each model has been milled from two sides (front and back), using the base of the 'statue' to fix the model. The statue has been CNC machined in pure white Carrara Marble (a full size statue), by Bertozzi Felice Srl in Italy. This is done on a special machine, with a diamond coated cutter, using much water as a coolant. In order to achieve a smooth result a ballnose cutter was used.

Left the marble milling machine, Right the resulting marble statue.

As said before, the artist is Mrs. Eja Siepman van den Berg (Beetsterzwaag, The Netherlands). The scanning has been performed by 3D Imaging (Antwerp, Belgium), who also performed the conversion from scanned data-points to 3D CAD geometry using the Surfacer (TM) reverse-engineering software. The triangle data were exported as a DXF-file in order to create a rendering in 3D Studio (TM), for DeskProto use it would also have been possible to use an STL-file produced by Surfacer.

Opposed the traditional method: Left the pattern model for handwork, Right the marble statue in progress.

This method of creating a marble statue by CNC machining is of course new. The traditional method is cutting by hand, using a (scaled) original as pattern for 3D measurements with all types of caliphers.

The resulting 'statue' in perspex

Subsequent result: the statue was machined on scale, now in transparent acrylic (perspex).
For tips on machining acrylic see the Perfume bottle project.