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Realism and Performance
Published in Aditi Majumder, M. Gopi, Introduction to Visual Computing, 2018
Bump mapping is a technique by which we can simulate the effects of small bumps on the surface of an object without changing the number of primitives, as shown in Figure 14.17. The two tori in this figure have the same number of triangles. But one looks much richer geometrically than the other due to the bumps. Note that both objects are also texture mapped with a blue and yellow texture. The bumps are simulated by perturbing the normal vectors in a predefined way so that the lighting changes in a manner that is consistent with the presence of the bump. This makes us perceive the bumps even if they are absent in the mesh.
B
Published in Phillip A. Laplante, Dictionary of Computer Science, Engineering, and Technology, 2017
bump mapping a technique used to increase the realism of a surface by changing how light reflects from that surface. Usually, the surface normal at a given point on a surface is used in the calculation of the brightness of the surface at that point. In bump mapping, the true surface normal n is perturbed a small amount <5n as a function of position on the surface. The perturbation can be regular, so as to give a regular textured shape to the surface, or it can be random, so as to increase the natural appearance of the surface. Part of what gives this technique its appeal is that the original surface maintains its original (usually smooth) shape, and the bump-mapping distortion is specified by a compact function of shape. This is usually much simpler and more compact than specifying the surface texture by explicitly representing the textured surface.
Accurate and Detailed Image-Based 3D Documentation of Large Sites and Complex Objects
Published in Filippo Stanco, Sebastiano Battiato, Giovanni Gallo, Digital Imaging for Cultural Heritage Preservation, 2017
Filippo Stanco, Sebastiano Battiato, Giovanni Gallo
In computer graphics applications, the texturing can also be performed with techniques able to graphically modify the derived 3D geometry (displacement mapping) or simulating the surface irregularities without touching the geometry (bump mapping, normal mapping, parallax mapping).
Virtual geographic environments for water pollution control
Published in International Journal of Digital Earth, 2018
Karsten Rink, Cui Chen, Lars Bilke, Zhenliang Liao, Karsten Rinke, Marieke Frassl, Tianxiang Yue, Olaf Kolditz
Our extensions of the Unity framework mentioned in the previous section are particularly useful for this case study. The complete region around Chao Lake integrated into the VGE has a size of over 5000 km2, here represented by roughly 200,000 triangles with a maximum edge length of 250 m. The corresponding aerial imagery (Figure 5(c)) has a pixel size of roughly 12.5 m which results in a detailed visualisation of the surface data despite not incorporating advanced methods such as bump mapping (see Figure 1 for a schematic of creating the textured terrain surface). However, the regions of interest for domain scientists are usually much smaller. For instance, we added a refined surface representation and image data for Chaohu City with a size of about 100 km2. The surface of this small region consists of over 300,000 triangles with a maximum edge length of 25 m, the aerial image has a pixel size of less than 3 m. This fine resolution is necessary to maintain a useful representation of the area when users are expected to zoom in very close to the surface. Also, integrating very detailed data sets such as the drainage system for the city (with a sub-metre resolution) requires similarly refined corresponding data for a visual assessment of the relation of data sets to each other.