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As a subject in computer science, data visualization or scientific visualization is the use of interactive, sensory representations, typically visual, ...
3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data (often Cartesian) that ...
In 3D computer graphics, 3D modeling (also known as meshing) is the process of developing a mathematical representation of any three-dimensionalsurface of object (either inanimate or living) via specialized software. The product is called a 3D model. It can be displayed as a two-dimensional image through a process called 3D renderingor used in acomputersimulation of physical phenomena. The model can also be physically created using 3D Printing devices.
3D models represent a 3D object using a collection of points in 3D space, connected by various geometric entities such as triangles, lines, curved surfaces, etc. Being a collection of data (points and other information), 3D models can be created by hand, algorithmically (procedural modeling), or scanned.
3D models are widely used anywhere in 3D graphics. Actually, their use predates the widespread use of 3D graphics on personal computers. Many computer games used pre-rendered images of 3D models as sprites before computers could render them in real-time.
Today, 3D models are used in a wide variety of fields. The medical industry uses detailed models of organs. The movie industry uses them as characters and objects for animated and real-life motion pictures. The video game industry uses them as assets for computer and video games. The science sector uses them as highly detailed models of chemical compounds. The architecture industry uses them to demonstrate proposed buildings and landscapes through Software Architectural Models. The engineering community uses them as designs of new devices, vehicles and structures as well as a host of other uses. In recent decades the earth science community has started to construct 3D geological models as a standard practice.
Almost all 3D models can be divided into two categories.
- Solid - These models define the volume of the object they represent (like a rock). These are more realistic, but more difficult to build. Solid models are mostly used for nonvisual simulations such as medical and engineering simulations, for CAD and specialized visual applications such as ray tracing and constructive solid geometry
- Shell/boundary - these models represent the surface, e.g. the boundary of the object, not its volume (like an infinitesimally thin eggshell). These are easier to work with than solid models. Almost all visual models used in games and film are shell models.
Because the appearance of an object depends largely on the exterior of the object, boundary representations are common in computer graphics. Two dimensional surfaces are a good analogy for the objects used in graphics, though quite often these objects are non-manifold. Since surfaces are not finite, a discrete digital approximation is required: polygonal meshes (and to a lesser extent subdivision surfaces) are by far the most common representation, although point-based representations have been gaining some popularity in recent years. Level sets are a useful representation for deforming surfaces which undergo many topological changes such as fluids.
The process of transforming representations of objects, such as the middle point coordinate of a sphere and a point on its circumference into a polygon representation of a sphere, is called tessellation. This step is used in polygon-based rendering, where objects are broken down from abstract representations ("primitives") such as spheres, cones etc., to so-called meshes, which are nets of interconnected triangles. Meshes of triangles (instead of e.g. squares) are popular as they have proven to be easy to render using scanline rendering. Polygon representations are not used in all rendering techniques, and in these cases the tessellation step is not included in the transition from abstract representation to rendered scene.
There are five popular ways to represent a model:
- Polygonal modeling - Points in 3D space, called vertices, are connected by line segments to form a polygonal mesh. Used, for example, by Blender. The vast majority of 3D models today are built as textured polygonal models, because they are flexible and because computers can render them so quickly. However, polygons are planar and can only approximate curved surfaces using many polygons.
- NURBS modeling - NURBS Surfaces are defined by spline curves, which are influenced by weighted control points. The curve follows (but does not necessarily interpolate) the points. Increasing the weight for a po
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Answers:limited range and limited accuracy. If you graph y = x on graph paper where x runs between 10 and +10, then the value of y cannot be determined if x = 11. Furthermore, the accuracy is limited to the resolution of the graph paper. So you could read y = 4.02 for x = 2 One more disadvantage: difficult to read, need training on how to read graphs. And another, graph paper is fragile, some water and your graph is gone. And another: you can't email it. .
Answers:This sounds like a physical topology, though us network admins don't use this terminology in our day-to-day. I usually call it a physical map. Logical topology drawings contain less-than-exact physical mappings but precise IP and routing protocol information for the internal network. Cable paths are physical maps for major cable runs between patch panels, data centers, core network devices, etc. Wiring grids are usually electrical diagrams, and network admins are usually only interested in locations of major sources of EMI (electro-magnetic interference.) Access topologies are physical and logical of all entry points into your network, including provider MPOEs (major points of entry), location/equipage of COs (central offices), etc.
Answers:Well the question isn't very clear, but basically, transformations are only done on vertices. There is no indication of color, only locations of objects and their enpoints. The vertices are the "input" for transformations. Rasterization, considers color and meshes, however, it processes them according to an algorithm. Depending on the sophistication of the hardware being used, the quality of the results can vary widely, but can still have certain aliasing effects etc, as mentioned. Taking an image that is generated in that way can't have the natural touch that comes from digital images created by a person, or taken from a camera. The exception might be for a program that was specifically created for this task (i.e. to humanize the rasterization process, which has been done, but not in real-time systems to my knowledge). So this is why mixing natural images with synthetic rasterizations will have problems...because the algorithms in the synthetic environment spoil the "naturalness" of the image.
Answers:Stem and leaf diagrams record data values in rows, and can easily be made into a histogram. Large data sets can be accomodated by splitting stems. Advantages: - Concise representation of data - Shows range, minimum & maximum, gaps & clusters, and outliers easily - Can handle extremely large data sets Disadvantages: - Not visually appealing - Does not easily indicate measures of centrality for large data sets Pictogram,line graph,pie chart,bar graph and scatterplot are normally classified as 'data handling' ways.