R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

268 Medical modelling
create relief textures on small rectangular samples (20 mm × 10 mm × 5 mm
high). A four-sided patch was drawn on the top surface of the blocks and
the ‘emboss with wrapped image’ function used to overlay the texture maps.
The scaling tools were used to gauge the approximate depth and density
of the required texture relief. The method of creating the textures is
described in detail in the experimental section below.
ThermoJet ® was used to produce the physical models of the test pieces
shown in Fig. 6.106. The details were produced with good visual effect.
However, the texture was neither suffi ciently detailed nor deep enough to
prove conclusive.
Pilot study 2
Another slightly larger test piece was created with an image that more
closely resembled a detailed skin texture. The texture was created on a
segment of anatomical data to assess the effect on a contoured piece rather
than the simple fl at area of the previous test pieces. The contoured test
piece was approximately 27 mm × 21 mm × 10 mm at its highest point. The
model was built using the ThermoJet ® RP machine, shown in Fig. 6.107.
Again, the depth was judged by eye and the resulting pattern suggested
that a realistic skin texture could be produced over a contoured surface.
Experimental series
Step 1 – producing the texture image A sample skin texture image was
located in the form of a two-dimensional grey scale bitmap, shown in Fig.
6.108. This image was then manipulated to produce a high contrast, black
6.106 Close-up photograph of the four trial pieces.