Efficient Real-Time Rendering of Building Information Models

A Building Information Model (BIM) is a powerful concept, since it allows both 2D-drawings and 3D-models of buildings or facilities to be extracted from the same source of data. Compared to a general 3D-CAD model a BIM is a different kind of representation, since it defines not only geometrical data but also information regarding spatial relations and semantics. However, because of the large number of individual objects and high geometric complexity, 3D-data obtained from a BIM are not easily used for real-time rendering without further processing. In this paper we present a culling system specifically designed for efficient real-time rendering of BIM’s. By utilizing the unique properties of a BIM we can form the required data structures without manual modification or expensive preprocessing of the input data. Using hardware occlusion queries together with additional mechanisms based on specific BIM-data, the presented system achieves good culling efficiency for both indoor and outdoor cases

Integrating Occlusion Culling and Hardware Instancing for Efficient Real-Time Rendering of Building Information Models

This paper presents an efficient approach for integrating occlusion culling and hardware instancing. The work is primarily targeted at Building Information Models (BIM), which typically share characteristics addressed by these two acceleration techniques separately – high level of occlusion and frequent reuse of building components. Together, these two acceleration techniques complement each other and allows large and complex BIMs to be rendered in real-time. Specifically, the proposed method takes advantage of temporal coherence and uses a lightweight data transfer strategy to provide an efficient hardware instancing implementation. Compared to only using occlusion culling, additional speedups of 1.25x-1.7x is achieved for rendering large BIMs received from real-world projects. These speedups are measured in viewpoints that represents the worst case scenarios in terms of rendering performance when only occlusion culling is utilized

Production of Virtual Models for Co-Creative Design in Construction Business

Game engine based technologies are becoming a more common platform for immersive head mounted displays. Due to the experiences derived from immersive demonstrations, construction industry has adopted the game engines as platforms to produce virtual models for different uses. A virtual model created in game engine can serve as the base for immersive visualization or physic-based simulation of different natural phenomena. Both examples provide information that interests designers and clients in construction industry. The research is divided into two parts. The first part is definition of a process for production of virtual models through empirical trials. The second part focuses how virtual models could be applied in co-creative design in construction business. The need for virtual models in co-creative design was researched by organizing themed interviews with different parties in construction business. The interviewees had either experience in co-creative design or modern technologies applied in construction and gaming industries. In addition, a case study for using a virtual model as a part of a facilitated workshop in co-creative design was done with help from University Properties of Finland Ltd. As the result of this thesis, a process for production of virtual models from different data sources in construction project was defined. The process is presented in three parts: data preparation, data refinement and import to the game engine, Unity3D. Performance requirements defined in research outlines can be achieved through different optimization techniques explained in the thesis. To illustrate the versatility of virtual models, two case examples explain how virtual models can be evolved into immersive visualizations of the design data on different platforms. Implementation to co-creative design process can be done via an organized workshop or by using the virtual model as a platform to provoke conversation between different parties in a construction project

Efficient Real-Time Rendering of Building Information Models

A Building Information Model (BIM) is a powerful concept, since it allows both 2D-drawings and 3D-models of buildings or facilities to be extracted from the same source of data. Compared to a general 3D-CAD model a BIM is a different kind of representation, since it defines not only geometrical data but also information regarding spatial relations and semantics. However, because of the large number of individual objects and high geometric complexity, 3D-data obtained from a BIM are not easily used for real-time rendering without further processing. In this paper we present a culling system specifically designed for efficient real-time rendering of BIM’s. By utilizing the unique properties of a BIM we can form the required data structures without manual modification or expensive preprocessing of the input data. Using hardware occlusion queries together with additional mechanisms based on specific BIM-data, the presented system achieves good culling efficiency for both indoor and outdoor cases