True-3D in Cartography—Current Hard- and Softcopy Developments - Geospatial Visualisation - page 48

Fig. 9 Rapid Prototyping at
the Institute of Geometry,
Dresden University of
Technology, Germany (from
Weiss and Buchroithner
2012 ). Further explanations:
see text below
3.1 Rapid Prototyping
Today it is possible to generate physical landscape models within a short time.
Rapid prototyping comprises different methods, e.g. stereolithography, 3D-print-
ing or milling. Rase ( 2009 , 2012 ) distinguishes between four main groups of rapid
prototyping techniques: removal or milling (Michelangelo Method), aggregation
(Rodin Method), transformation (Chillida Method), and laser subsurface
engraving or laser etching (Dürer Method). The removal method implies the
removal of material from a block of wood or plastic to form the desired model.
Computer-controlled milling is such a removal method. In contrast to the removal
method the aggregation method works vice versa: loose material like a jelly or a
powder is merged layer by layer to form a final model, e.g. by heat or glue.
For example stereolithography and 3D-printing use this principle to generate relief
models (see Fig. 9 ). Since the first 3D printer by ZCorporation ( www.ZCorp ) has
been introduced in 2001, a colouring of the model during the printing process is
now possible. This has replaced a subsequent manual colouring stage. For the
production of 3D models the aggregation method might have the highest potential
(see also Rase 2009 , 2012 ). Some USA companies like Cubic Technologies and
Stratasys, Inc. ( www.CubicTechnologies , www.Stratasys ) use different types of
''3D-printing'' such as laminated object modeling or fused deposition modeling
(FDM ). Further, 3D Systems, Inc. runs a production line of 3D-printing, stere-
olithography (SLA ) and selective laser sintering (SLS )( www.3DSystems ). It is
hard to make statements to what extent these technologies have already been
applied for the production of physical landscape models.
The central specimen created with a 3D-printer in Fig. 9 represents the famous
Eiger Northface in Switzerland based on data generated by the Institute for Car-
tography at the Dresden University of Technology, Germany.
The transformation method forms material by pressure and heat. With the help of
a mould a planar thermoplastic foil is transformed into a foil which corresponds to