Search

Abstract:: Background: With the rapid development of Web3D technologies, the online Web3D visualization, particularly for complex models or scenes, has been in a great demand. Owing to the major conflict between the Web3D system load and resource consumption in the processing of these huge models, the huge 3D model lightweighting methods for online Web3D visualization are reviewed in this paper. Methods: By observing the geometry redundancy introduced by man-made operations in the modeling procedure, several categories of lightweighting related work that aim at reducing the amount of data and resource consumption are elaborated for Web3D visualization. Results: By comparing perspectives, the characteristics of each method are summarized, and among the reviewed methods, the geometric redundancy removal that achieves the lightweight goal by detecting and removing the repeated components is an appropriate method for current online Web3D visualization. Meanwhile, the learning algorithm, still in improvement period at present, is our expected future research topic. Conclusions: Various aspects should be considered in an efficient lightweight method for online Web3D visualization, such as characteristics of original data, combination or extension of existing methods, scheduling strategy, cache management, and rendering mechanism. Meanwhile, innovation methods, particularly the learning algorithm, are worth exploring.

Background: In recent years, with the rapid development of mobile Internet and Web3D technologies, a large number of web-based online 3D visualization applications have emerged. Web3D applications, including Web3D online tourism, Web3D online architecture, Web3D online education environment, Web3D online medical care, and Web3D online shopping are examples of these applications that leverage 3D rendering on the web. These applications have pushed the boundaries of traditional web applications that use text, sound, image, video, and 2D animation as their main communication media, and resorted to 3D virtual scenes as the main interaction object, enabling a user experience that delivers a strong sense of immersion. This paper approached the emerging Web3D applications that generate stronger impacts on people's lives through “real-time rendering technology”, which is the core technology of Web3D. This paper discusses all the major 3D graphics APIs of Web3D and the well-known Web3D engines at home and abroad and classify the real-time rendering frameworks of Web3D applications into different categories. Results: Finally, this study analyzed the specific demand posed by different fields to Web3D applications by referring to the representative Web3D applications in each particular field. Conclusions: Our survey results show that Web3D applications based on real-time rendering have in-depth sectors of society and even family, which is a trend that has influence on every line of industry.

Understanding and simulating human behavior during the evacuation is essential in cognitive computing, which can be used to guide pedestrians to evacuate quickly and to avoid a potential hazard. In this paper, we propose a model to simulate the human behavior for evacuation from a classroom. Specifically, first, we give an improved evacuation model based on cellular automata, which consists of the static floor field and the dynamic floor field. Then, we present the detailed algorithms for calculating both the floor fields. The static floor field is calculated using an A-star algorithm, which can be used to solve the evacuation environments with and without obstacles. The dynamic floor field is calculated based on the impact of the number of pedestrians in each exit area on evacuation. Finally, the calculation method of pedestrian movement probability and the model evolution rules are given. The simulation experiments using our model have been conducted, and comparisons between our model and some state-of-the-art evacuation models are also conducted. The experimental results show that the model is effective and can reproduce the evacuation experiments conducted by students well. The model is expected to yield the optimal evacuation plan from the indoor environment.

In the field of medical imaging, many medical image data can be rebuilt into 3-D medical models for use in medical education and analysis. In fact, the 3-D medical models help ordinary people (including patients and students) to more easily understand and learn medical knowledge. In addition, with the rapid development of Web3D technology, the demand for 3-D visualization technology based on the web browser increases. However, the limited bandwidth and low load capacity of the browser have seriously restricted the development of technology. Therefore, this paper proposes a framework to better show 3-D skeleton shapes. In particular, mesh compression is one of the most effective methods to achieve a fast transmission data process. In addition, because of the poor rendering capabilities of the browsers, it is notably difficult to render the entire model at once. Moreover, it often makes the browser crash; thus, the transmitted model data are only rendered once. In addition, a mesh segmentation algorithm is proposed to realize component-wise rendering and lightweight for shape. A voxel-based component repetition method is used to detect the repetitive components; thus, we can perform matrix transformation to finish the repetitive-component Web3D visualization, i.e., lightweight for shape. Finally, the related experiments are performed to validate our proposed framework. The results show that the proposed framework is feasible and superior.

Intelligent CAD garment design becomes more and more popular by attracting the attentions from both manufacturers and professional stylists. The existing garment CAD systems and clothing simulation software fail to provide user-friendly interfaces as well as dynamic recommendation during the garment creation process. In this paper, we propose an intelligent hypertouch garment design system, which dynamically predicts the possible solutions along with the intelligent design procedure. User behavioral information and dynamic shape matching are used to learn and predict the desired garment patterns. We also propose a new hypertouch concept of gesture-based interaction for our system. We evaluate our system with a prototype platform. The results show that our system is effective, robust, and easy to use for quick garment design.

We present an intelligent method to automatically detect repetitive components in 3D mechanical engineering models. In our work, a new Voxel-based Shape Descriptor (VSD) is proposed for effective matching, based on which a similarity function is defined. It uses the voxels intersecting with 3D outline of mechanical components as the feature descriptor. Because each mechanical component may have different poses, the alignment before the matching is needed. For the alignment, we adopt the genetic algorithm to search for optimal solution where the maximum global similarity is the objective. Two components are the same if the maximum global similarity is over a certain threshold. Note that the voxelization of component during feature extraction and the genetic algorithm for searching maximum global similarity are entirely implemented on GPU; the efficiency is improved significantly than with CPU. Experimental results show that our method is more effective and efficient than that existing methods for repetitive components detection.