# Residential Buildings Complex Boundaries Generation Based on Spatial Grid System
## 2 Related Work
This research shows that, with extensive layout database and adequate neural network training, the problem of automatically generation of building layouts can be solved using existing boundaries as an input. [PERSON] et al. [19] used a Bayesian network trained on real-world data to design an architectural program that generates floor plans using stochastic optimization. The described solution enables the generation of simple and complex building forms, but with low levels of complexity. The basic approach, described in this paper, is focused on the creation of very complex forms instead. That is why the former related work reference is used for the comparative analysis of derived results, presented in detail in Section 5. [PERSON] [20] proposed a method for automatic construction of irregular floor plans from the graphical patterns as an input where the accuracy of the input area of the rooms in the described results is not of great importance. The boundary is derived from the input image of an object shape. [PERSON] [21] used natural graphic images to generate a building layout plan. [PERSON] et al. [22] developed a method for exploring different building layouts based on simulated annealing. Procedurally generating building shapes with grid-based constraints based on the cellular automata approach is widely adopted in the field of architectural and urban design based on the cellular automata approach. Patterns generated by cellular automata systems are used in architectural design for form exploration [23; 24; 25; 26]. Several methods have been developed based on cellular automata systems. [PERSON] and [PERSON] [27] developed a system for the generation of 3D buildings based on [PERSON]'s Game of Life system [28]. [PERSON] and [PERSON] [29] use cellular automata for the generation of high-density residential buildings, addressing density, accessibility, and natural light. Some researchers explored cellular automata generation results as the first step and developed architecture form enveloping some cells or the entire form [30; 31]. However, the application of cellular automata systems in the domain of architectural design is faced with several limitations. According to [26; 32; 33], the degree of complexity for even simple architectural outcomes suggests that generating a complete architectural design in this manner is resource-demanding and, in general, probably even not possible. The main challenge is to find the solution that preserves an acceptable balance between complexity in architectural design and formal rules of cellular automata systems. Summarizing the current state-of-the-art analysis it is possible to conclude that there are several approaches used as a foundation to specification, modeling, and design of tools for automated generation of building boundaries, with emphasis on 2D or 3D building geometry layout inclusion. The comparative analysis of related work relevant to this article topics, with respect to selected key factors (dimensionality, interior layout inclusion, and boundary type) is presented in Table 1.  
The analyzed results, however, show that the prevalent trend mainly focuses on the simple boundary type forms because either complex forms appeared challenging for the particular approach or they were not considered at all.