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The Diverse Domain
Published in Aditi Majumder, M. Gopi, Introduction to Visual Computing, 2018
Processing refers to methods or techniques that are used on models of objects or phenomena usually driven by objectives like accuracy, performance (usually faster rendering) or application dependent efficiencies. Examples of such processing includes model simplification or stripification. Model simplification is the process where an object is stored at different levels of details that use different number of primitives to represent the same object. Objects need larger number of primitives when represented at higher level of details and fewer primitives when represented at lower level of details. When rendering, the right level of detail to be rendered is chosen based on how far the object is from the viewer. When the object is farther away, a lower level of detail would suffice for acceptable appearance but can be rendered much more efficiently in much less time due to fewer primitives. This is illustrated in Figure 12.3.
Quality Criteria for Simulator Images: A Literature Review
Published in Florian Jentsch, Michael Curtis, Eduardo Salas, Simulation in Aviation Training, 2017
Pieter Padmos, Maarten V. Milders
Level of detail (LOD) is a feature that minimizes polygons to be calculated while keeping the number of visible details on objects sufficiently high. In order to provide LOD, objects are stored in various versions, in which progressively smaller details are modeled. For large observation distances in which the smallest details fall within the system's spatial resolution, the coarser object versions are generated; during approach, more detailed versions are generated (Wyckoff, 1989). The LOD feature is especially important for NOE flights and driving, for which it is often desirable to display many details at a short distance.
Building Information Modeling and Code Checking
Published in Nawari O. Nawari, Building Information Modeling, 2018
Understanding the degree of information required for the elements in the model plays a significant role in ensuring its utilization for code compliance–checking purposes. The Level of Development (LOD) is the degree to which the element’s geometry and attached information have been identified as necessary and sufficient by project team members to perform the required tasks when using the BIM model. In other words, the Level of Detail is simply how much detail is included in the model objects. In terms of terminology, Level of Detail can be thought of as input to the element, while LOD defines reliable outcomes.
A clipping algorithm for real-scene 3D models
Published in International Journal of Digital Earth, 2023
Jianhua Chen, Xu Liu, Bingqian Wang, Jian Lu
The target area (e.g. outcropping strata) of oblique photogrammetry generally includes a large range of ground objects covered by many images. The number of points in a point cloud generated with these images is very large (Vetrivel et al. 2018). If the TIN model consisting of numerous points is separately stored under the same resolution, the rendering efficiency of the model will be significantly reduced. To solve this problem, the concept of levels of detail (LODs) is usually employed for 3D models (Biljecki et al. 2016). LODs have the following characteristics: as the root node decreases, the model representation range decreases, whereas the point cloud density and model resolution increase. However, LOD-based 3D models generated with oblique photogrammetric data have the following problems: Due to sensor errors, model reconstruction errors, and other factors, these models are partially distorted, and the local displays of these models are poor, which affects the overall quality of the models (Wu et al. 2018);There are irrelevant features (e.g. buildings in a 3D model of outcropping strata) in these models, which causes data redundancy and can even affect the analysis of the target features of interest.
Identifying optimal graphical level of detail to support orienting with 3D geo-visualizations
Published in Spatial Cognition & Computation, 2022
Aaron L. Gardony, Dalit D. Hendel, Tad T. Brunyé
In 3D computer graphics, level of detail (LOD) management is a fundamental principle (Cudworth, 2018; Danovaro, De Floriani, Magillo, Puppo & Sobrero, 2006). The goal of LOD management is simple, to adaptively reduce the computational complexity of rendering 3D content while attempting to maintain visual appearance (Luebke et al., 2002). This is accomplished by first decimating a detailed high poly model into lower resolution variants that visually resemble the original but contain fewer polygons and concomitantly have smaller file sizes and processing demands (Pajarola & Gobbetti, 2007). Once multiple LODs are created for the same model, a LOD management system stores them dynamically and exchanges them within the scene to optimize overall system performance. As network, storage, and computational resources increase, so too can LOD. Through LOD management, visualization of complex 3D models can be optimized to significantly reduce storage requirements, computer memory utilization, processing and rendering time, and network bandwidth requirements (Bektaş, Çöltekin & Straumann, 2012; Bodum, 2005; Coltekin & Reichenbacher, 2011). LOD management systems select the appropriate LOD based on several factors like screen size, the distance of the virtual camera to the content, and available computational resources with the ultimate goal of delivering the highest possible detail whenever possible based on current context (Glander, 2013).