## 2 Background
### Related Work  
The use of ontologies in the domain of engineering design and, in particular, regarding CAD systems was presented in a recent review of ontology-focused feature modeling technology by [PERSON] and [PERSON] [32]. As one result of the analyses, features regarding manufacturing information are abundant, while support for function integration in terms of pictorial design intent is surprisingly under-represented. In this domain, [PERSON] et al. [33] and [PERSON] et al. [34] reviewed ontological representations of design intent from different perspectives. [PERSON] et al. [34] proposed the formalization of two main understandings of design intent in engineering. One is the Functional Basis approach, defined by Stone and Wood [35], where functions are understood as operations on flows performed by artifacts. This description was integrated with process ontologies in [PERSON] et al. [33]. The second refers to the Functional Representation approach developed by [PERSON] [36], which defines functions as behaviors of artifacts (Functional concept ontologies in [PERSON] et al. [33]). From these reviews, there are three approaches that share the idea of a CAD-embedded ontological knowledge representation for design characteristics and intent as domain knowledge. **DANE and SBF models:** DANE (Design by Analogy to Nature Engine) is the latest application that reuses bionic knowledge for future product generations based on Structure-Behavior-Function (SBF) models according to [37]. Structure is represented in terms of components, the substances contained in the components, and connections among the components. Function is represented as a schema that specifies its preconditions and postconditions. The function schema contains a reference to the behavior that accomplishes the function. Behavior is represented as a sequence of states and transitions between them [37]. The SBF model is used as knowledge representation for a number of knowledge applications (e.g., KRITIK [38], IDEAL [39], ARCHYTAS [40], DANE [41]). **OntoSTEP:** The Product Data Exchange format STEP (Standard for Exchange of Product model data), which describes product data models in application protocols (APs), allows engineering data to be interchanged [42]. The first concept for an ontology, which is used for the exchange of product data, was published in 2005 with Product Semantic Representation Language (PSRL) [43]. The idea was further developed, and additional APs were integrated [44; 45]. OntoSTEP is the representation of STEP product models in Web Ontology Language. It was introduced in 2009 and is continuously being expanded [46; 47]. **Semantic Alliance:** Semantic Alliance is the core component of multiple approaches. It was first published in 2009 and further developed until 2013 [48; 49]. In principle, semantic information is annotated to the CAD in order to verify, at an early stage, whether product properties can be guaranteed. Three main components have been described: a knowledge base called Planetary, an interface to the CAD environment called Alex, and an interoperability component called Sally. All three components form the Semantic Alliance. The semantic information is mostly document-based. It is modeled with the help of XML-based markup languages in a machine-readable and machine-processable format [50]. None of the approaches or methods found were developed to explicitly support design automation. Therefore, each approach lacks different requirements stated in the introduction that hinder or even prevent its use for design automation. Most importantly, they lack the ability to reuse the design process as knowledge. Although the SBF model offers the possibility to represent processes with the help of states and transitions, these are only used to represent product behaviour after development. Furthermore, the analyzed approaches support the conceptualization rather than the design of the product.