Experiments in Rapid PrototypingWritten by Paul Bourke
The testing here of the ZCorp colour rapid prototyping machine were geared towards determining how far one can push the technology and how useful it might be for mathematical and scientific visualisation. While these particular machines are one of the most advanced and general, they still place some significant constraints on the models they can represent. Perhaps the most serious involves the infusion process after the model has been built, the model can be extra delicate during this infusion process. This places an extra constraint on the thinnest structure over and above what the machine process can create.
The machine in question has a volume of about 200 x 200 x 250 mm. The first tests below were intended to investigate the value of creating solid models of mathematical shapes, in this case supershapes.
Character from an animated movie (by Russell Scott)
The following model is somewhat more demanding, firstly the wings are very thin, and secondly the model is not free standing so until it is infused with hardener it can't easily support itself. Indeed most damage to the model occurred not by the "printing" process but by the infusion process which removed the structural strength from a number of parts of the model, this seems to occur when the infusing fluid saturates right through the model.
The STL format used to represent the monochrome models here has no support for colour. The software that drives the machine expects VRML descriptions for colour models. VRML models are not difficult to create in code given parametric equations for the surfaces. The quality of the colour, see elliptic torus, was surprisingly good. This model was created intentionally with a continuous colour ramp to test this.
With regard to mathematical visualisation, it is immediately obvious once it is placed on a table that the tetrahredral ellipse is perfectly flat on all sides, something that is not at all obvious from computer based exploration.
Elliptic Torus and Tetrahredral Ellipse
Other examples (2007)ASKAP telescope model
Rocks and fossils
Sirovision cliff face models
In the following a terrain (cliff) was recreated, the original surface and texture map is automatically generated by taking two photographs of the cliff face. Software called "Sirvision" can then recreate a 3D mesh surface from the two images, one of the images can additionally be applied as a texture map.
In general successful rapid prototyping require solid objects, not just (infinitely thin) surfaces. This is certainly true for the ZCORP machines, while the model can be structurally strong after curing, it can be quite delicate beforehand. The surface mesh here is simply extruded a fixed distance, this works because the surfaces here don't have "caves".
The following are two images of the modelled surface.
400 million year old Placoderm embryo
Examples from 2012-2014
Photogrammeterically derived bust of Socrates, UWA.