R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

Suitable technologies identifi ed
Case studies 267
From the review of currently available technologies and the required
parameters stated above, the following technologies were selected.
Prosthesis design was to be performed using FreeForm ® CAD software,
including the addition of texture. The completed prosthesis design would
be produced from this design fi le using the ThermoJet ® wax printing
process.
6.17.5 Methods
Case studies were conducted that explored utilizing the technologies identifi
ed. Firstly, the application of two-dimensional texture maps to create
three-dimensional relief on anatomical models was explored using
FreeForm ® CAD and ThermoJet ® RP. This was followed by a series of test
pieces designed and manufactured to test the ability of the selected CAD
software to create and export texture relief that would provide a range of
realistic skin textures and the capability of the RP machine to reproduce
these textures to the required accuracy.
Assessment
Subjective analysis of the results was used in this study since the nature of
prosthesis production and texture detailing results in complex forms that
do not provide convenient datum or reference surfaces from which to
measure accuracy. By defi nition, prostheses are one-off custom-made appliances
made to fi t individual patients. Therefore, it is not practical to perform
the type of repeated statistical analysis that would be commonly encountered
in series production or mass manufacture. The aesthetic outcome and
accuracy of prostheses is subjectively assessed by the prosthetist and subsequently
the patient.
The RP produced patterns were fi rst assessed against the CAD models.
Secondly, the level of detail in each of the model sets was assessed by a
qualifi ed and experienced prosthetist and the ability of the technologies to
create and manufacture realistic and convincing skin textures was commented
on.
6.17.6 Case studies
Pilot study 1
An initial pilot study was used to assess the capability of FreeForm ® in
creating texture relief and ThermoJet ® in reproducing the detail. A series
of texture images were converted into high contrast black and white images
using photographic manipulation software. These images were used to