Advanced Modeling Techniques For Computer Graphics Engineering Essay

Advanced Modeling Techniques For Computer Graphics Engineering Essay In the past thirty years, modeling techniques in computer graphics have evolved significantly as the field has matured and attempted to portray the complexities of nature. Polygonal models, patches, points, and lines are insufficient to represent the complexities of natural objects and intricate man-made objects in a manageable and controllable fashion. Higher-level modeling techniques have been developed to provide an abstraction of the model, encode classes of objects, and allow high-level control and specification of the model. The goal of these advanced modeling techniques is to provide a concise, efficient, flexible, and controllable mechanism for specifying and animating models of complex objects and natural phenomena. Most of these advanced modeling techniques can be considered procedural modeling techniques: code segments or algorithms are used to abstract and encode the details of the model instead of explicitly storing vast numbers of low-level primitives. The use of algori thms unburdens the modeler/animator of low-level control, provides great flexibility, and allows amplification of his efforts through parametric control: a few parameters to the model yield large amounts of geometric details (Smith [1984] called this â€Å"database amplification†). This survey examines several types of procedural techniques, including fractals, grammar-based models, volumetric procedural models, implicit surfaces, and particle systems. Fractals [Peitgen et al. 1992] have a precise mathematical definition, but in computer graphics their definition has been extended to refer generally to models with a large degree of self-similarity: subpieces of the object appear to be scaled down, possibly translated and rotated versions of the original object. Along these lines, Musgrave [Ebert et al. 1994] define a fractal as â€Å"a geometrically complex object, the complexity of which arises through the repetition of form over some range of scale.† Many natural objects exhibit this characteristic, including mountains, coastlines, trees, plants (e.g., cauliflower), water, and clouds. Fractals can generally be classified as deterministic or non-deterministic (also called random fractals), depending on whether they contain randomness. Random fractals have been used extensively in computer graphics to model natural objects, most notably terrain. Most fractal terrain-generation algorithms work through recursive subdivision an d pseudorandom perturbation. An original surface is defined and divided equally into subparts. New vertices are added and pseudorandomly displaced from the original surface, with a displacement magnitude that decreases at each iteration as the frequency increases. Therefore, the first iteration gives the large peaks on the surface, and later subdivisions add small-scale detail. Only the parameters for controlling the random-number generator, the level of subdivision, and the â€Å"roughness† of the surface are needed to define an extremely complex terrain. Recent work in fractals has included the simulation of diffusion-limited aggregation Copyright  © 1996, CRC Press. ACM Computing Surveys, Vol. 28, No. 1, March 1996 (DLA) models and the use of multi-fractals [Ebert et al. 1994], which allows different fractal dimensions (degrees of â€Å"roughness†) in the models to simulate natural terrain better. GRAMMAR-BASED MODELS Grammar-based models, primarily Lsystems [Prusinkiewicz and Lindenmayer 1990], also allow natural complexity to be specified with a few parameters. Grammar- based models have been used by many authors, including Lindenmayer, Prusinkiewicz, and Fowler, to produce remarkably realistic models and images of trees, plants, and seashells. These models use formal languages, parallel graph grammars called L-systems, to describe natural structures algorithmically and are closely related to deterministic fractals in their self-similarity, but fail to meet the precise mathematical definition of a fractal.1 An L-system is a formal language where all the rules are applied in parallel to provide a final â€Å"sentence† describing the object. In the L-system, each terminal symbol represents a part of the object or a directional command to be interpreted by a three-dimensional drawing mechanism (turtle graphics). A â€Å"sentence† for a tree would contain words describing each branch, its length, size, and branching angle, when it develops, and its connection in the tree. More complex L-systems, IL-systems, include context- sensitivity, word age information, and probabilistic rule evaluation, which allows each plant to be unique. Recent work in L-systems allows better developmental models, more advanced biologically based growth models, incorporation of more growth parameters, and environmental effects. VOLUMETRIC PROCEDURAL MODELS Another procedural modeling technique, volumetric procedural modeling (also called hypertextures, volume density functions, and fuzzy blobbies), uses algorithms to define and animate threedimensional volumetric objects and natural phenomena [Ebert et al. 1994]. These techniques have been used to model natural phenomena such as fire (Stam and Inakage), gases such as smoke, clouds, and fog (Ebert, Perlin, Sakas, Stam), and water (Ebert, Perlin). The volumetric procedures take as input a point location in space, a time parameter, and parameters that describe the object being modeled, and return the density and color of the object for that location in space. Complex volumetric phenomena can, therefore, be described with a few parameters. Perlin has successfully used this technique to create realistic rock arches, woven fabric, smoke, and fur [Ebert et al. 1994], basing his procedures on a statistical simulation of turbulence and random noise to give natural-looking complexity to the obje cts. Ebert et al. [1994] have used similar functions to model and animate steam, fog, smoke, clouds, and solid marble. These procedural techniques allow the use of simple simulations of natural complexity (noise, turbulence) to speed computation, but also allow the incorporation of physically based parameters, where appropriate and feasible. This flexibility is one of the many advantages of procedural techniques. IMPLICIT SURFACES While previously discussed techniques have been used primarily for modeling the complexities of nature, implicit surfaces [Wyvill et al. 1986; Wyvill and Gascuel 1995] (also called blobby molecules, metaballs, and soft objects) have mainly been used for modeling organic shapes, complex man-made shapes, and â€Å"soft† objects that are difficult to animate and describe using more traditional techniques. Implicit surfaces are a more concise representation than parametric surfaces and provide flexibility in modeling and animating soft objects. Im- 1Some authors consider L-systems to be deterministic fractals. 154 †¢ David S. Ebert ACM Computing Surveys, Vol. 28, No. 1, March 1996 plicit surfaces are iso-valued surfaces created from blending primitives (skeletal elements) represented by implicit equations of the form F(x, y, z) 5 0. Each primitive is a procedure that returns a functional value for the field defined by the implicit equation. A key feature of implicit surfaces is the procedural, smooth, often volume-preserving blending of primitives to form quite complex surfaces from simple primitives. Objects are defined as offsets (isosurfaces) from a series of blended skeletal elements (points, lines, polygons, spheres, ellipsoids, and so on). Modeling and animation of implicit surfaces is achieved by controlling the skeletal elements and blending functions, which provide complex models and animations from a few parameters (another example of data amplification). Recent work in implicit surfaces [Wyvill and Gascuel 995] has extended their use to character modeling and animation, human figure modeling, and representing rigid objects through the addition of CSG (constructive solid geometry) operators. PARTICLE SYSTEMS Particle systems differ from the previous four techniques in that their abstraction is in control of the animation and specification of the object. Particle systems do use a large database of geometric primitives to represent natural objects (â€Å"fuzzy objects†), but the animation, location, birth, and death of the particles representing the object are controlled algorithmically. Particle systems are most commonly used to represent natural phenomena such as fire, water, clouds, snow, rain, grass, and trees [Reeves and Blau 1985]. A particle- system object is represented by a large collection (cloud) of very simple geometric particles that change stochastically over time. The procedural aspect and main power of particle systems allow the specification and control of this extremely large cloud of geometric particles with very few parameters. Besides the geometric particles, a particle system has controllable stochastic particleanimation procedures that govern the creation, mov ement, and death of the particles. These animation procedures often include physically based forces to simulate effects such as gravity, vorticity, conservation of momentum, and energy. Particle systems pose special rendering problems because of the large number of primitives, but specialized rendering techniques, including probabilistic rendering algorithms, have been developed to render particle systems [Reeves and Blau 1985]. FUTURE DIRECTIONS Advanced modeling techniques will continue to play an important role in computer graphics. As computers become more powerful, the complexity that can be rendered will increase; however, the ability of humans to specify more geometric complexity (millions of primitives) will not. Therefore, procedural techniques, with their ability to amplify the user’s specification and control, are the only viable alternative. The ability of these techniques to specify and control incredibly realistic and detailed models with a small number of user-specified parameters will evolve. More work will be done to allow high-level control and specification of models in user-understandable terms, while more complex algorithms and improved physically based simulations will be incorporated into these procedures. Finally, automatic generation of the procedural models through artificial evolution techniques, similar to those of Sims [1994], will greatly enhance the capabilities and uses of these advanced modeling techniques.

Encounters with peope of different cultures

Encounters with people of different cultures in their own countries or communities 2 3 4 5 Coping with the customs of host countries or communities, e. g. rules and courtesies that local people observe and may expect me to observe. Encountering the different customs of people from other cultures, e. g. dress, spec al occasions, etc. Adapting to the rhythm of life in other cultures, e. g. getting used to different meal times etc. Integrating with the customs or behaviour of host countries, e. g. eginning to use forms of greeting that is very different from my own. Encounters with different cultures in the host university Clarifying areas of uncertainty about university arrangements, e. g. describing what I am used to and asking what happens in the other culture. Adapting to other administrative and academic practices, e. g. using unfamiliar procedures to complete a work task. Coping with different formal ties, e. g. learning new ways of showing respect to senior colleagues from other cultures.Relating to fellow students from other cultures, e. g. learning what they like to talk about during breaks. Being aware of issues to be avoided with a different cultural group, e. g. learning what opics seem to be avoided and what the group's views are likely to be about a current political situation. Building bridges between colleagues ot my own culture and those ot a ditterent culture, e. g. sensing that someone of my culture has said the wrong thing and explaining the misunderstanding to both sides.Section 3 A continuing record of intercultural encounters In this section you can record many kinds of intercultural experiences and encounters that you feel have helped you develop your intercultural skills. In each record, describe what happened and how this enabled you to advance your nowledge and understanding of – or attitude to – intercultural ‘events' ( interactions with people from other cultures, etc). Date: 31109/2012 As soon I arrived at the rent ed place, I found out that my flatmates were both Spanish and I feared that I would be left apart due to my level of Spanish,.However, to my surprised they were both very welcoming and even try their best to understand my poor Spanish and were willing to show me around and give me very helpful tips in relation, to transportation, nightlife and food consumption. Place: Pozuelo de Alarcon The suggestions made by flatmates were quite helpful, on the next day I went to rder my student travel card wish made really easier to travel around Madrid. Their travel system is very similar London travel system which actually work base on the zones you have to move around. However, the store was closed from 12 to 14 0'clock as well as every store around.Such thing was very strange to me and as my flatmates explained it is common thing in Spain for stores to be close at such time due to their weather conditions is too hot work there for thy take a break. It is at that point were a have notice that weather conditions have a huge effect on Spain Culture. Place: Groningen University The team work experience with the guys, gave me the opportunity to improve my communication skills, because we could express one's need, wants and opinion without offending the sensitiveness of the other guys.In addition, I believe I strengthen my Teambuilding skills, as I was the person who motivated the others. The members recognised that, and I was the point of communication between the others. From this experience I realised how much I would like to work for the Human Resources, as I believe to be able to maintain group cooperation and support, and to keep a group updated how it is moving forward to the achievement of the goals. Date: 31/10/2012 On 31/10/12 1 had a presentation to be done together with 3 more students. It was me, a Spanish girl, a Romanian guy, and a Dutch guy.The Dutch guy most of the times we had meeting was quite rude with the other guys. He wanted the work to be done, and he was actually the first not to do it. The day of the presentation, I had a small argument with him. The presentation went well, we scored 7. 2. This guy, during the conversation with our coach said that he was the best and that the other guys, us, did not have the competencies to do the presentation. Place: At first, I got really upset and offended, as he should not dear to say these bad things to his team member.Secondly, I believe he should have told us in a private conversation, as all of us were really embarrassed, and we all thought that what he was saying was not actually true. Finally, I spoke with him and he apologised about what happened with the guys and l. I hope he understood that he should not criticise others, when he is the first person who makes mistakes. Date: 03/11/2012 In these days I was reflecting how the Dutch academic semester works so differently trom the English semester. Here, every semester is made trom two periods.In each period there are at least three mo dules to study, therefore exams, reports, group works and presentations to do. At my university, we only have four modules for semester, whilst here there are at least six for each semester. I could see how I improved time management planning and organizational skills. Place: Groningen My skills improved because the amount of work to do was higher than my expectations. In fact, I had to develop goals for my personal achievements, and identify tasks to be accomplished. In addition, I learnt how prioritise tasks and take esponsibilities for the decisions I made.Based on the above please prepare a SWOT analysis of the stage that you believe are at in terms of cross cultural competence; (i. e. strengths and weaknesses) and where you would like to get to by January. What are the opportunities for enhancing your competence and what are the threats which may thwart your endeavours if left untackled? Studying the first semester of the second year in ESIC located in Madrid, Spain enables me to break down barriers as well as communicate and interact with people from different cultures in ways beyond no lecture room or university hall can.

The Deception of Trifles Gender Roles in the Play by...

In the 19th Century, women had different roles and treated differently compared to today’s women in American society. In the past, men expected women to carry out the duties of a homemaker, which consisted of cleaning and cooking. In earlier years, men did not allow women to have opinions or carry on a job outside of the household. As today’s societies, women leave the house to carry on jobs that allow them to speak their minds and carry on roles that men carried out in earlier years. In the 19th Century, men stereotyped women to be insignificant, not think with their minds about issues outside of the kitchen or home. In the play Trifles, written by Susan Glaspell, the writer portrays how women in earlier years have no rights and men†¦show more content†¦In the kitchen, the dishes are dirty, bread is sitting out on the counter, and everything is in disarray. The County Attorney is disturbed, because the kitchen is not clean. The men assume that Mrs. Wrig ht must have not been a very tidy person. In this time era, men expected women to keep the house tidy and clean, cheerful, and decorated according to the County Attorney in Trifles; he states, â€Å"It’s not cheerful. I shouldn’t say she had the homemaking instinct† (1031). Men during this era think that women should only be in the house worrying about what the inside of a house should look. In the County Attorney’s mind, the house should have been warm, clean, organized, and presenting a happy feeling. This is a demonstration of how hard a woman’s life is when she is expected to be when a man’s views think of how a woman should be in the household, for example a slave to cooking, cleaning, and sewing. As shown in the beginning of the play, the men leave the women in the kitchen to gather some of Mrs. Wright’s items she requested as if this is where these women belong. The men go upstairs and out to the farmhouse to investigate for clues for a motive to prove that Mrs. Wright is guilty of the murder of her husband. The men never investigate the kitchen for any clues since they feel there is no significance in the kitchen. The kitchen is an area for women to do cooking and cleaning, which makes them feel there is nothing important in this area. MenShow MoreRelatedTrifles, By Susan Glaspell Essay2136 Words   |  9 Pageswomen’s roles were primarily of a domestic nature. Trifles by Susan Glaspell indicates that a man’s perspective is entirely different from a woman’s. The one-act play, Trifles, is a murder mystery which examines the lives of rural, middle-aged, married, women characters through gender relationships, power between the sexes, and the nature of truth. The play, written in the early 1900s, long before the women’s movement and while men considered women their possessions. In the story of Trifles, it isRead MoreEssay about Treatment of Women in Hamlet and Trifles2 666 Words   |  11 PagesWomen in Hamlet and Trifles Of all Shakespeare’s thirty-seven plays, perhaps the best known and loved is Hamlet, Prince of Denmark. Many people think that it is unforgettable because of its poetic language and style. But, while these are factors that mark the play as a classic, it remains timeless because it explores many of the issues that are still important to people today. These issues, including loyalty to family and country, protecting loved ones, and deception are still prevalentRead More Hamlet and Trifles: Aspects of the Past Relevant to the Present1966 Words   |  8 PagesHamlet and Trifles: Aspects of the Past Relevant to the Present The Elizabethan Era under the rule of Queen Elizabeth I in England not only produced an expansion of growth in the suburbs and a more unified nation, but also introduced the world’s most famous playwright of all times, William Shakespeare. During this period of greatest artistic achievement, Shakespeare, who produced about thirty- seven plays as well as many other great works, created what is considered his greatest achievement

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