## 3 DL-Based Ontology
### Entities for Support Generation  
Support generation is a process planning task that aims to generate the minimum amount of support structure that best meets the build and quality requirements to build a part [5]. The main inputs of this task include a 3D model in a build orientation for a part to be built and specific build and quality requirements on the part. Its output is a 3D model with support structure in a build orientation. To generate the support structure for a 3D model in a given build orientation, the first step is to detect the overhang area on the model that needs to be supported. In existing support generation methods, this detection is generally carried out using the angles between the normal vectors of triangular facets and the build orientation. When the angle corresponding to a triangular facet is greater than a certain value, the area corresponding to the triangular facet is considered to be the overhang area that needs to be supported [5]. After detecting the supported overhang area, a specific shape of support structure will be generated for it. So far, a number of different shapes of support structures for AM part build have been developed [5]. The support structures suitable for LPBF part build mainly include lattice support structure [66], cellular support structure [67], unit cell support structure [68], pin support structure [69], Y support structure [69], IY support structure [69], and tree support structure [70]. In practice, which shape of support structure \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Data Relation** & **Domain** & **Range** & **Meaning** \\ \hline _hasInput_ & _ProcessPlanning_ & owl:Thing & A process planning task that has input of \\ _hasOutput_ & _ProcessPlanning_ & owl:Thing & A process planning task that has output of \\ _hasSearchAlgorithm_ & _SearchBasedMethod_ & xsd:string & A search based method that has search algorithm of \\ _hasGenerationApproach_ & _RuleBasedMethod_ & xsd:string & A rule-based method that has generation approach of \\ _hasSelectionApproach_ & _RuleBasedMethod_ & xsd:string & A rule-based method that has selection approach of \\ _hasObjective_ & _ProcessPlanning_ & _Objective_ & A process planning task that has objective of \\ _hasEncodedFormat_ & _3 dModel_ & xsd:string & A 3D model that has encoded format of \\ _Slice_ & _xsd:string & A slice that has encoded format of \\ _hasAngleAlpha-deg_ & _AnglePair_ & xsd:double & An angle pair that has rotation angle \(\alpha\) of \\ _hasAngleBeta-deg_ & _AnglePair_ & xsd:double & An angle pair that has rotation angle \(\beta\) of \\ _hasCoordinateX_ & _UnitVector_ & xsd:double & A unit vector that has x coordinate of \\ _hasCoordinateY_ & _UnitVector_ & xsd:double & A unit vector that has y coordinate of \\ _hasCoordinateZ_ & _UnitVector_ & xsd:double & A unit vector that has z coordinate of \\ _hasGeometricForm_ & _3 dModel_ & _Form_ & A 3D model that has geometric form of \\ _hasRecommendedMethod_ & _PartOrientation_ & _Method_ & An orientation task that has recommended method of \\ _hasOrientation_ & _3 dModel_ & BO & A 3D model that has build orientation of \\ _isDescribedBy_ & _BuildOrientation_ & _AnglePair_ & A build orientation that is described by an angle pair of \\ & _BuildOrientation_ & _UnitVector_ & A build orientation that is described by a unit vector of \\ \hline \hline \end{tabular} Note: \(BO\) stands for _BuildOrientation_.  
\end{table} 
Table 4: Domain, range, and meaning of sixteen relations in part orientation. Figure 4: An ontological view of part orientation for LPBF. to use is usually determined by the used process planning tool, since each process planning tool provides its specific shapes of support structures. Support generation is usually coupled with optimising the selected shape of support structure to minimise its total volume and improve part quality. To date, many optimisation methods have been presented within academia.