# An Indoor Space Model of Building Considering Multi-Type Segmentation
## 2 Conceptual Framework of Multi-Level Indoor Space Model
### Spatio-Temporal Segmentation Characteristics of Indoor Space  
Indoor space segmentation is to gradually separate the internal space of an independent building into subspaces by components to meet different functional requirements. Therefore, there are significant segmentation characteristics between rooms. Describing and expressing the temporal and spatial segmentation characteristics of indoor space is the premise of recognizing multi-detail level indoor space. From the perspective of geography, this paper further explains the temporal and spatial segmentation characteristics of indoor space.  
The spatial segmentation characteristics specifically refer to the geometric division of the indoor space by the components. According to different spatial segmentation characteristics, indoor space segmentation can be divided into:  
1. Entity segmentation. Entity segmentation refers to the use of objectively existing building components, furniture components, and other entities to segment the geometry of indoor space. By spatially limiting the boundaries of indoor space objects, the enclosure forms an objective physical boundary that meets the needs of specific user functions. The components will block people's sight and walking route, so through physical segmentation, a relatively closed space will be obtained, thereby ensuring the privacy characteristics of the indoor space.
2. Virtual segmentation. Virtual segmentation refers to the use of \"empty\" boundaries provided by imaginary boundary components to separate two adjacent indoor spaces. The geometry of the imaginary boundary components serves as the boundary between two adjacent spaces. Fictitious boundary components are usually not displayed, and there is no other attribute information (such as materials). The virtual partition of the indoor space is not completely closed on the boundary, forming a relatively open space (semi-indoor space).  
The temporal characteristics of indoor space segmentation mainly refer to the time sequence of the division of indoor space by components. According to the temporal segmentation characteristics, indoor space segmentation can be divided into:  
1. The first segmentation process is to partition the indoor space from the natural environment by building components, as shown in Figure 1. The space boundary can be constrained by building component entities such as walls, columns, and floor slabs, which separate the indoor space from the natural space. The building shell component separates the internal space of the building from the external natural environment, and the floor component divides the internal space of the building into different story spaces in the vertical direction. Inside each story space, building internal components continue to divide the story space into a single room space with different functions.
2. The second segmentation is the space division within a single space using indoor furnishing components. The room is divided into several areas through the arrangement of indoor furnishing components, each area being a subspace with different activity functions. The first segmentation process is essentially the construction process of the main structure of the building, and the second segmentation corresponds to the process of interior decoration.