Animation on the web: a survey <s> Transmission Of Data <s> This paper presents a compression scheme for mesh geometry, which is suitable for mobile graphics. The main focus is to enable real-time decoding of compressed vertex positions while providing reasonable compression ratios. Our scheme is based on local quantization of vertex positions with mesh partitioning. To prevent visual seams along the partitioning boundaries, we constrain the locally quantized cells of all mesh partitions to have the same size and aligned local axes. We propose a mesh partitioning algorithm to minimize the size of locally quantized cells, which relates to the distortion of a restored mesh. Vertex coordinates are stored in main memory and transmitted to graphics hardware for rendering in the quantized form, saving memory space and system bus bandwidth. Decoding operation is combined with model geometry transformation, and the only overhead to restore vertex positions is one matrix multiplication for each mesh partition. <s> BIB001 </s> Animation on the web: a survey <s> Transmission Of Data <s> A feature-oriented generic progressive lossless mesh coder (FOLProM) is proposed to encode triangular meshes with arbitrarily complex geometry and topology. In this work, a sequence of levels of detail (LODs) are generated through iterative vertex set split and bounding volume subdivision. The incremental geometry and connectivity updates associated with each vertex set split and/or bounding volume subdivision are entropy coded. Due to the visual importance of sharp geometric features, the whole geometry coding process is optimized for a better presentation of geometric features, especially at low coding bitrates. Feature-oriented optimization in FOLProM is performed in hierarchy control and adaptive quantization. Efficient coordinate representation and prediction schemes are employed to reduce the entropy of data significantly. Furthermore, a simple yet efficient connectivity coding scheme is proposed. It is shown that FOLProM offers a significant rate-distortion (R-D) gain over the prior art, which is especially obvious at low bitrates. <s> BIB002 </s> Animation on the web: a survey <s> Transmission Of Data <s> 3D animations have been widely used in the movie and gaming industries. However, the huge storage requirements of dynamic mesh data make it difficult for a number of applications such as rendering, transmitting over a network, etc.This study proposes a multiresolution representation for 3D animation. The results show that the coarse animation appears by using only 10% of the original faces. More detailed animation appears by using 80% of original faces, but only requires 3% of original storage space. Consequently, this approach enables a continuous level of detail for dynamic 3D mesh sequences. <s> BIB003 </s> Animation on the web: a survey <s> Transmission Of Data <s> With the development of Web3D technologies, the delivery and visualization of 3D models on the web is now possible and is bound to increase both in the industry and for the general public. However the interactive remote visualization of 3D graphic data in a web browser remains a challenging issue. Indeed, most of existing systems suffer from latency (due to the data downloading time) and lack of adaptation to heterogeneous networks and client devices (i.e. the lack of levels of details); these drawbacks seriously affect the quality of user experience. This paper presents a technical solution for streaming and visualization of compressed 3D data on the web. Our approach leans upon three strong features: (1) a dedicated progressive compression algorithm for 3D graphic data with colors producing a binary compressed format which allows a progressive decompression with several levels of details; (2) the introduction of a JavaScript halfedge data structure allowing complex geometrical and topological operations on a 3D mesh; (3) the multi-thread JavaScript/WebGL implementation of the decompression scheme allowing 3D data streaming in a web browser. Experiments and comparison with existing solutions show promising results in terms of latency, adaptability and quality of user experience. <s> BIB004 </s> Animation on the web: a survey <s> Transmission Of Data <s> Recent advances in Web technology, especially real-time 3D content using WebGL, require an efficient way to transfer binary data. Images, audio and video have respective HTML tags and accompanying data formats that transparently handle binary transmission and decompression. 3D data, on the other hand, has to be handled explicitly by the client application. In contrast to images, audio and video, 3D data is inhomogeneous and neither common formats nor compression algorithms have been established for the Web. Despite the many existing formats for binary transmission of 3D data none has been able to provide a general binary format for all kinds of 3D data including meshes, textures, animations, and materials. Existing formats are domain-specific and fixed on a certain set of input data and thus too specific to handle other types of data. Blast is a general container format for structured binary transmission on the Web that can be used for all types of 3D scene data. Instead of defining a fixed set of encodings and compression algorithms Blast exploits the code on demand paradigm to provide a simple yet powerful encoder-agnostic basis to leverage existing domain-specific solutions and compression techniques. Because streaming is of primary importance for a good user experience Blast is designed on the basis of self-contained chunks to enable JavaScript clients to utilize Web Workers for parallel decoding and to provide early feedback to the user. <s> BIB005 </s> Animation on the web: a survey <s> Transmission Of Data <s> A problem that still remains with today's technologies for 3D asset transmission is the lack of progressive streaming of all relevant mesh and texture data, with a minimal number of HTTP requests. Existing solutions, like glTF or X3DOM's geometry formats, either send all data within a single batch, or they introduce an unnecessary large number of requests. Furthermore, there is still no established format for a joined, interleaved transmission of geometry data and texture data. Within this paper, we propose a new container file format, entitled Shape Resource Container (SRC). Our format is optimized for progressive, Web-based transmission of 3D mesh data with a minimum number of HTTP requests. It is highly configurable, and more powerful and flexible than previous formats, as it enables a truly progressive transmission of geometry data, partial sharing of geometry between meshes, direct GPU uploads, and an interleaved transmission of geometry and texture data. We also demonstrate how our new mesh format, as well as a wide range of other mesh formats, can be conveniently embedded in X3D scenes, using a new, mini-malistic X3D ExternalGeometry node. <s> BIB006
Animation of a 3D object or scene requires transmitting extra data, beyond that which is required to render the scene statically. Depending on the context, this extra data may dwarf the original static data source. Transmission of data via the internet uses basic and well established protocols such as TCP and UDP. At the lowest level, the basic problem associated with these networking protocols resolve around latency (TCP), accuracy (UDP) and bandwidth (both). Latency, in this context, can be perceived as the time needed to fully refine the 3D object since the time of application start up, and the time to refine the model based on the user interaction and different point of views. It is one of the most critical issues that a low powered client device can have, but considering that nowadays the so-called "low powered" mobile devices are equipped with so much processing power that the negative impact on the interactivity of the application mostly depends on network bandwidth and how the transmission is structured. Despite dramatic improvements in recent years, mobile network connections still largely suffer from low bandwidth, and moreover these characteristic change with mobility and geographic location. Therefore, it is important that the data is transmitted in a structured manner and there is minimum possible interaction between server and client. As BIB005 points out, current formats allow for compression and binary transmission but lack any internal structure for transferring more than a single resource of a specific type. Thus, the number of requests to the server increases with the number of resources within a scene or object. In which case, if bandwidth is sufficient, latency becomes the limiting factor. The transmission of 3D data is usually a two-step approach. First, the object structure is sent to the client. Second, the handling and processing of the data at the client end. The 3D data format for the web can be categorized as either text-based or in binary format. Formats encoded as text are human readable, thus their file size is bulkier. But the native HTTP's GZIP compression does an excellent job of compressing it. A typical 3D scene or object structure(s) contains references to all the external resources such as meshes, images, textures, and animation data. The XMLHttpRequest (XHR) API is used to request each resource separately and they are transmitted using JSON, XML, binary XHR or any of the domain specific formats. Another transmission data format suggested by  , is to use 2D images to encode the arrays representing the coordinates, normals and other attributes. This would allow us to use various audio-video encoding and compression techniques, and on the client side the data can be passed as texture in WebGL to the GPU, bypassing all the computation. But this can cause some problem in some older devices. The Web is in need of a binary transmission format for 3D data that allows for domain-specific or at least a general standard of compression technique for animation data. As outlined in ], every binary transmission format for the Web has to be designed to reduce the number of requests, handle network characteristics and facilitate client applications in providing a good user experience. All approaches discussed here address only a subset of the challenges that need to be solved for a general, common, and efficient transmission of 3D data. With regards to 3D asset transmission, a prominent problem is the lack of progressive streaming of all relevant mesh and texture data, with a minimal number of HTTP requests. Furthermore, there is still no established format for a joined, interleaved transmission of geometry data and texture data. [ BIB006 aims to minimize the number of HTTP requests, by progressively transmitting an arbitrary number of mesh data chunks within a single SRC file. This file contains the reference to all the resources of data and progressively downloads them. Another approach to solving the bandwidth problem is to use caching strategies; caching is necessary to improve the performance by avoiding redundant data transfer. Caching prevents sending large amount of data, but it requires bidirectional communication which is not available HTTP protocol. WebSockets can be used, which could improve latency as it supports a full duplex communication channel. Web Sockets allow the client and server to stream data bi-directionally but requires a protocol understood by both ends. However, no general protocol for the transmission of 3D data has been established yet. To improve upon the lack of progressive downloads, there is already W3C draft in the works for the next standards for HTTP 2.0 and Streams API, which will bring progressive downloads to its feature list. A more challenging problem worthy of further investigation is 1-D streaming BIB003 ], which combines the geometry and connectivity operators into the more general refining operators. To achieve different progressive representations for animation, other progressive methods such as valance-driven can be compared. Gobbetti et al.  proposed a method that also uses image-based mesh description format. It resamples the model data in order to build a tight atlas parametrization of the mesh geometry. This enables them to use the atlas images also for multi-resolution transmission and rendering via simple mipmap operations. Similar to X3DOM's BinaryGeometry node, BIB001 propose to reduce the size of binary mesh data for efficient storage and transmission, using a straightforward local quantization scheme. They argue that geometry compression for mobile graphics requires a careful choice of the compression method in order to maintain interactive decompression rates. BIB004 state some of the issues that are overlooked by the scientific community: Existing compression techniques give more importance to compression ratio, where as in online transmission, improving quality of level of detail is more important than being clever and gaining a few extra bits. Few recent researchers have taken LOD into serious consideration. BIB002 BIB003 Perfect level of detail management requires efficient handling of the 3D object attributes such as color, texture and other information regarding the data and animation. They need to be progressively maintained and processed as LOD of geometry and connectivity is handled. Some example of recent techniques are BIB003 BIB006   .