3D Modeling
3D modeling: is process of developing a mathematical, wireframe representation of any three-dimensional 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 rendering or used in a computer simulation of physical phenomena. The model can also be physically created using 3D Printing devices.
Models may be created automatically or manually. The manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting.
3D models, the product of modeling procedures, are often created with special software applications called 3D modelers. Being a collection of data (points and other information), 3D models can be created by hand, algorithmically (procedural modeling), or scanned. Though they most often exist virtually (on a computer or a file on disk), even a description of such a model on paper can be considered a 3D model.
3D models are widely used anywhere 3D graphics are used. 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. 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.
A model is not technically a graphic until it is visually displayed. Due to 3D printing, 3D models are not confined to virtual space.
Modeling processes: There are three popularly used means by which to represent a model:
· Polygonal modeling - Various vertices on an xyz grid are mapped out. The vertices are connected in a linear fashion to form a polygonal mesh. Used for example by Maya 3d.
· NURBS modeling - Curves are formed by defining control points and attaching a "weight" to each one. The curve follows (but does not necessarily interpolate) the points. Increasing the weight for a point will pull the curve closer to that point. NURBS are particularly suitable for organic modelling. Used for example by Rhino3d.
· Splines & Patches modeling - Curves which define the surface directly (Splines) used for example by Hash Animation:Master.
The modeling stage consists of shaping individual objects that are later used in the scene. There are a number of modeling techniques, including:
Modeling can be performed by means of a dedicated program (e.g., Maya, 3DS Max, Blender, Lightwave, Modo) or an application component (Shaper, Lofter in 3DS Max) or some scene description language (as in POV-Ray). In some cases, there is no strict distinction between these phases; in such cases modelling is just part of the scene creation process (this is the case, for example, with Caligari trueSpace and Realsoft 3D).
Complex materials such as blowing sand, clouds, and liquid sprays are modeled with particle systems, and are a mass of 3D coordinates which have either points, polygons, texture splats, or sprites assign to them.
Representation: 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.
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Class Title
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Lecture Hours
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Lab Hours
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Practicum Hours
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Instructional Hours
|
|
Microsoft Word XP and Windows XP
|
60
|
30
|
|
90
|
|
AutoCAD
|
90
|
60
|
|
150
|
|
Rhino 400 (Jewelry & 3-D Design)
|
60
|
30
|
45
|
135
|
|
Total
|
210
|
120
|
45
|
375
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