R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

Data quality
Physical reproduction 69
Whilst the majority of orientation decisions are arrived at by considering
the fi nal model’s shape and size the computer data used to build it may
also have an infl uence on the choice of build orientation. The choice of data
format could limit the options available for orienting the model. For
example, if a 2 1 / 2D format is used, such as an SLC fi le, then the choice of
orientation is fi xed when the data is created. Usually these formats are
created in the same orientation as the original scan data, and this may
provide a higher quality data fi le. The advantages of the data format in
terms of quality and effi ciency may override the other orientation considerations.
The data formats and their various advantages and disadvantages
are described in Chapter 4.
5.1.7 Basic principles of medical modelling – sectioning,
separating and joining
Prior to preparing an RP build, it is worth considering the nature of the
model and its intended use before fi nalising the data. There are several
considerations to address relating to the overall size of the model, whether
it is one structure or a number of related structures and whether their
positional relationship is important. For these reasons, it may become
necessary to section, separate or join different parts to make the model or
models required.
Sectioning
5.6 The effect of orientation on model support.
Sectioning may be done when selecting the data from the original scan data
or could be done by splitting the export data fi les, such as STL fi les. The