## 3 Printing Information Model for Additive Manufacturing of Concrete Structures  
In this section, the printing information model is developed, aiming to formalize the information necessary for designing and planning concrete printing projects through a single semantic model based on object-oriented modeling concepts, materialized in the form of a semantic model and an ontology. Since the terminology with respect to \"semantic models\" and \"models\" differs depending on the field of research, it must be noted that in this study, a \"semantic model\" is considered a metamodel to be instantiated into specific \"models\", in compliance with [35]. In other words, the models, representing extracts of the real world, are instances of the metamodel, which formally defines the structure, semantics, and constraints of the models. Metamodels are used as schemas to develop software applications as well as databases and may be extended to support future needs of the extracts of the real world. The model developed for printing information modeling, hereinafter referred to as the PIM model, focuses on extrusion-based AM of concrete structures and describes the semantics of material-process interactions. The printing information model is developed in four steps: (i) conceptual modeling, (ii) formal modeling, (iii) verification, and (iv) validation. In the first step, aspects and interactions within concrete printing are conceptualized in the form of a knowledge map and structured as a semantic model. The knowledge map aids in categorizing input parameters in AM data modeling into process-related, material \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Information Unit** & **Attributes** & **Rqd.** & **Opt.** \\ \hline Process data & The process data will have been specified prior to developing the additive manufacturing model. The process data include printing strategy (e.g., layer-by-layer strategy, infill pattern, and nozzle height), boundary conditions (e.g., process constraints and machine constraints), and machine parameters (e.g., printing speed, acceleration, and pump pressure). & X \\ \hline Sliced model & The sliced model will have been generated prior to developing the additive manufacturing model. The sliced model includes slicing parameters (i.e., scale factor, layer height, extrusion width, and build orientation) and support structure parameters (i.e., support pattern and support spacing). & X \\ \hline Material specifications & The material specifications will have been defined prior to developing the additive manufacturing model. The material specifications include design parameters for the main material (e.g., concrete type, design strength, design moduli, maximum aggregate size, slump, and open time), support material (e.g., material type and design strength), and reinforcement material (e.g., material type and design strength). & X \\ \hline Project properties & \begin{tabular}{c} General properties of the additive manufacturing project: \\ \(\bullet\) \\ \end{tabular} & \begin{tabular}{c} Project name; \\ Engineer. \\ \end{tabular} & X \\ \hline Toolpath & \begin{tabular}{c} Path for the printhead to follow: \\ \(\bullet\) \\ \end{tabular} & \begin{tabular}{c} X \\ Process parameter profile; \\ Material parameter profile. \\ \end{tabular} & X \\ \hline Results of material models & \
\begin{tabular}{c} Results of numerical modeling of the material behavior according \\ to the material specifications. \\ \end{tabular} & X \\ \hline Results of manufacturing process simulations &
\begin{tabular}{c} Results of the simulation of the additive manufacturing process \\ according to the process data, the sliced model, and the \\ material behavior. \\ \end{tabular} & X \\ \hline Feedback & Feedback from the printing process (Post-process). & X \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Information exchange requirements for AM models, with prerequisites highlighted in gray. related, and geometry-related information.