**4.2. Data manipulation**

**4. 3D image design**

94 New Trends in 3D Printing

the following steps.

Dim: 40 × 24 × 25 mm).

**4.1. Data preparation**

Raw data obtained from 3D camera systems often require further processing prior to 3D printing. Depending on the anatomical location of the prosthesis, mesh editing can consist of

CAD generation of the missing facial part can take various forms. Data capture of unaffected areas of the face can be undertaken and images 'mirrored' in order to virtually replace those affected or missing. This may be suitable for missing ears or orbital areas where there are usually bilateral structures. However, this may not be appropriate or possible for single or isolated structures including nasal structures or where surgery has already been undertaken to remove the affected part. Alternatively, open‐source CAD databases are now increasingly available—www.turbosquid.com—and these can offer CAD users direct links to download‐ able content. These may include non‐specific facial shapes covering a wide range of anatomical form, from those considered 'generic' to those with interesting or characteristic features. Although easily accessible, there are some issues with these sources. Although geometrically accurate, the peripheral area can be quite variable and not suited to cover the affected areas in specific patients. Additionally, the surface detail can be highly faceted and unsuitable for direct modelling. However, these files can provided good starting points for CAD design and allow adaptation to enable conformation to the affected area. Various software can be used to alter theses captured or acquired data files including 3‐Matic (Materialise, Leuven, Belgium). These can then be used to alter the surface detail and to refine the geometry in order to provide

individual and bespoke characteristics for the missing facial part (**Figure 3**).

**Figure 3.** Image detailing manipulation of the CAD prosthesis to refine the shape and fit of the final part (Approx. part

The acquired and adjusted model can then be blended into the affected area to create a smooth margin that will contact the facial tissues. Furthermore, CAD prostheses occasionally require hollowing and thinning until the prosthesis is between 2 and 3 mm thick and this can again be undertaken with various software packages. Finally, the model is then trimmed to remove all unnecessary data prior to printing. As previously indicated, information for attachments can then be imported and merged with the prepared CAD prosthesis and be precisely aligned to produce a good retentive element and fit.
