Browsing by Subject "Computer-aided design."

Now showing 1 - 14 of 14

Open Access
3D hair design and key frame animation in real time
(2008) Başarankut, Barkın
Computer generated animations of humans, animals and all other kinds of objects have been studied extensively during the last two decades. The key for creating good animations has been to correctly imitate the behaviors of real objects and reflect these into computer generated images. With the rapid development of computer technology, creating realistic simulations has become possible, and the most striking components of these realistic animations happen to be the most dynamic (moving) parts; hair, in the case of human animations. With the development of high quality hair animations, the concern is not only creating physically correct animations, but also controlling these animations. An implementation of a key frame hair animation creation system, supported by a hair design tool, helping to model and animate hair easily, and provide these functionalities in real time is the aim of the proposed system. This work reviews several hair animation and sketching techniques, and proposes a system that provides a complete level of control (capable of controlling even the individual hair strands) of key frame animation and hair design in real time.
Open Access
3D hair sketching for real-time hair modeling and dynamic simulations
(2008) Aras, Rıfat
Hair has been an active research area in computer graphics society for over a decade. Different approaches have been proposed for different aspects of hair research such as modeling, simulating, animating and rendering. In this thesis, we introduce a sketch-based tool making use of direct manipulation interfaces to create hair models and furthermore simulate the created hair models under physically based constraints in real-time. Throughout the thesis, the created tool will be analyzed with respect to different aspects of the problem such as hair modeling, hair simulation, hair sketching and hair rendering.
Open Access
Collaborative environments to enhance creativity of design students : use of collaborative creativity support tools
(2011) Karakaya, Ahmet Fatih
Collaboration and creativity are integral parts of design education process. Tools to support collaborative design process, as well as tools to support creativity in the process now being used together in design education. Therefore in this study, the Collaborative Creativity Support Tool (CCST) is proposed and applied to the design process that is conducted both synchronously and asynchronously. CCST is composed of design students, knowledge domain and design field. MOODLE learning environment is utilized for collaboration and enhancing creativity processes in knowledge domain, and Google SketchUp 3D modeling tool is used in the design field. Data collection is composed of observations during and after the study, surveys, correspondence logs, 3D models, interviews and statistics that were obtained by MOODLE forum logs. To evaluate effectiveness of CCST, segment analysis over demographic data, communication frequencies, communication codes, indicators of creativity, analysis of creativity in design education is used. Findings of the empirical research indicate that CCST supported design students in both collaborative and creative processes.
Open Access
Comparing designers' cognitive behaviors in geometry-based and parametric 3D modeling environments
(2014) Tünger, Çetin
Digital design area has been constantly developed by scientific studies, but it is observed that studies in this area have mostly focused on the technical aspects of the subject (i.e. development of new tools and courses). User, tool, and process are three fundamental elements of a digital design system, so there is a need for studies on users and processes as well as tools. This study was carried out to understand and compare the cognitive behaviors of designers in conventional geometry-based and parametric 3D modeling environments within the framework mentioned above. While the geometry-based modeling tools are based on creation and the modification of the geometry, parametric modeling environments include an algorithmic structure underlying the form generation process. The study utilized Rhino as a geometric tool and Grasshopper as a parametric 3D tool. Six design students participated in the study. The data was collected by protocol analysis method and analyzed with a content-oriented coding scheme developed in this study. Results indicated that the cognitive actions of designers were significantly different in geometric and parametric modeling environments.
Open Access
A computer assisted universal design (CAUD) plug-in tool for architectural design process
(2008) Afacan, Yasemin
Managing universal design process is a highly complex and challenging design task due to its multi-parameter characteristics. It becomes even more difficult while accommodating the needs of people with diverse impairments in architectural design process. Thus, this study aims to propose the development and implementation of an innovative computer-assisted universal design plug-in tool (CAUD) in the initial design phase that is compatible with the existing three-dimensional design software, SketchUp. Based on the theories and researches, the cognitive design strategies are analyzed for the efficiency of the knowledge support of the CAUD plug-in tool. Thus, the capabilities of the plug-in tool are defined according to the accommodation with an ideal cognitive strategy during analysis, synthesis and evaluation operations. Moreover, to achieve challenges of selecting the right set of universal design requirements within the plug-in tool, a prioritization technique that is based on the hybridization of the two techniques, the Planning Game (PG) and Analytic Hierarchy Process (AHP) using a cost-value approach is proposed. Through the proposed hybrid technique, requirement–design relationships are computed and the cost-value ratios of requirement priorities are represented. The study that is developed for universal kitchen design applications yielded a significant contribution to the universal design problem-solving process in a computer-aided design (CAD) environment. Finally, the results of the acceptability studies also showed that the CAUD plug-in tool is found in general useful, understandable, efficient, helpful and satisfactory.
Open Access
An evolutionary basic design tool
(2010) Akbulut, Dilek
As a creative act, design aims at achieving innovative solutions to fulfill the requirements provided in the problem definition. In recent years, computational methods began to be used not only in design presentation but also in solution generation. The study proposes a design methodology for a particular basic design problem on the concept of emphasis. The developed methodology generates solution alternatives by carrying out genetic operations used in evolutionary design. The generated alternatives are evaluated by an objective function comprising an artificial neural network. The creative potential of the methodology is appraised by comparing the outputs of test runs with the student works for the same design task. In doing so, three different groups of students with diverse backgrounds are used.
Open Access
Exploring vertical navigation within a virtual environment : a staircase experience
(2012) Memikoğlu, İpek (Sancaktar)
Architectural cues are configured by architects in the initial phase of design process. Local architectural cues within an environment can aid individuals during navigation and influence their spatial orientation. Staircases, as a feature of local architectural cues that provide access to the other floors in a multi-level building can have an impact on vertical navigation. This study focuses on the issue of vertical navigation during virtual navigation by integrating the individual characteristics and the geometric attributes of a staircase pair within two different multi-level desktop virtual environments (VEs). The angle between the cue pairs with respect to the same observation point is altered in order to determine the staircase pair that is more efficient in navigation. Circulation paths, gender differences, navigational abilities and cue pairs are considered to be factors that affect staircase preferences for ascending and descending. For the VE with a 180° difference between the cue pairs, there was a relationship between the ascending and descending staircases. Further analysis indicated that the staircase preference in ascending was either related to the first or last visited rooms on the ground floor. For the VE with a 90° difference between the cue pairs, no relationship was found between the ascending and descending staircases as well as with any other factor. There was no significant relationship between gender and staircase preference except for the descending staircase with 180° difference between the cue pairs and was in favor of females. In addition, there was no significant relationship between the navigational abilities and staircase preferences.
Open Access
A novel CAD algorithm for the analysis of printed geometries
(1997) Kınayman, Noyan
An efficient and accurate computer aided design (CAD) software for the electromagnetic simulation of passive microwave components, fabricated in planar stratified media, is developed in this work. The numerical technique employed in this software is based on the spatial-domain method of moments (MoM) in conjunction with the closed-form Green’s functions. Since the computational efficiency is a major issue in CAD softwares, the spatial-domain MoM is significantly improved in this respect with the use of the closed-form Green’s functions and closed-form expressions for the MoM matrix entries. Vertical metalizations in the form of via holes and shorting pins, which are the indispensable parts of the most microwave circuits, are also modeled very efficiently and incorporated into this formulation. The resulting approach is applied to some realistic microwave circuits and planar antennas, with and without vertical metalizations, to validate the formulation. It is also demonstrated that the formulation developed in this work can be efficiently used with an optimization algorithm for design purposes. The results obtained from the formulation proposed in this work are compared to those obtained from a commercial electromagnetic analysis software.
Open Access
PLAWE: A piecewise linear circuit simulator using asymptotic waveform evaluation
(1994) Topçu, Satılmış
A new circuit simulation program, PLAWE, is developed for the transient analysis of VLSI circuits. PLAWE uses Asymptotic Waveform Evaluation (AWE) technique, which is a new method to analyze linear(ized) circuits, and Piecewise Linear (PWL) approach for DC representation of nonlinear elements. AWE employs a form of Pade approximation rather than numerical integration techniques to approximate the response of linear(ized) circuits in either the time or the frequency domain. AWE is typically two or three orders of magnitude faster than traditional simulators in analyzing large linear circuits. However, it can handle only linear(ized) circuits, while the transient analysis problem is generally nonlinear due to the presence of nonlinear devices such as diodes, transistors, etc.. We have applied the AWE technique to the transient simulation of nonlinear circuits by using static PWL models for nonlinear elements. But, finding a good static PWL model which fits well to the actual i — v characteristics of a nonlinear device is not an easy task and in addition, static PWL modelling results in low accuracy. Therefore, we have developed a dynamic PWL modeling technique which uses SPICE models for nonlinear elements to enhance the accuracy of the simulation while preserving the efficiency gain obtained with AWE. Hence, there is no modelling problem and we can adjust the accuracy level by varying some parameters. If the required level of accuracy is increased, more simulation time is needed. Practical examples are given to illustrate the significant improvement in accuracy. For circuits containing especially weakly nonlinear devices, this method is typically at least one order of magnitude faster than HSPICE. A fast and convergent iteration method for piecewise-linear analysis of nonlinear resistive circuits is presented. Most of the existing algorithms are applicable only to a limited class of circuits. In general, they are either not convergent or too slow for large circuits. The new algorithm presented in this thesis is much more efficient than the existing ones and can be applied to any piecewise-linear circuit. It is based on the piecewise-linear version of the Newton-Raphson algorithm. As opposed to the NewtonRaphson method, the new algorithm is globally convergent from an arbitrary starting point. It is simple to understand and it can be easily programmed. Some numerical examples are given in order to demonstrate the effectiveness of the presented algorithm in terms of the amount of computation.
Open Access
Proposal for a software model based on the critical analysis of packages used in interior architecture
(2008) Bozdağ, Burcu Gökçen
Interior architectural education and practice employ various different general purpose software packages. Nonetheless, this study claims that as none of packages is developed specifically for interior architectural design process and purposes, both interior architecture education and market seek ways to fulfill their specific needs. This study aims at proposing a model for domain specific software for interior architecture. Within this conception, initially, general purpose and domain specific CAAD software used in interior architecture are defined. Then, selected software are analyzed according to ‘drawing’, ’transformation’, ‘view’, ‘rendering’ and ‘other’ features. Interior architectural domain specific requirements are obtained as a result of these analyses and comparisons. Consequently, questionnaires and interviews are performed with interior architectural students and professionals in order to determine user needs. The analysis of the user needs provide significant background information about software features and quality attributes of the proposed model.
Open Access
Real-time fur modeling with simulation of physical effects
(2012) Arıyürek, Sinan
Fur is one of the important visual aspects of animals and it is quite challenging to model it in computer graphics. This is due to rendering and animating high amounts of geometry taking excessive time in our personal computers. Thus in computer games most of the animals are without fur or covered with a single layer of texture. But these current methods do not provide the reality and even if the rendering in the game is realistic the fur is omitted. There have been several models to render a fur, but the methods that incorporate rendering are not in real-time, on the other hand most of the real-time methods omit many of the natural aspects , such as; texture lighting, shadow and animation. Thus the outcome is not sufficient for realistic gaming experience. In this thesis we propose a real-time fur represantation that can be used on 3D objects. Moreover, we demonstrate how to; render, animate and burn this real-time fur.
Open Access
Representation, editing and real-time visualization of complex 3D terrains
(2012) Koca, Çetin
Terrain rendering is a crucial part of many real-time computer graphics applications such as video games and visual simulations. It provides the main frame-ofreference for the observer and constitutes the basis of an imaginary or simulated world that encases the observer. Storing and rendering terrain models in real-time applications usually require a specialized approach due to the sheer magnitude of data available and the level of detail demanded. The easiest way to process and visualize such large amounts of data in real-time is to constrain the terrain model in several ways. This process of regularization decreases the amount of data to be processed and also the amount of processing power needed at the cost of expressivity and the ability to create interesting terrains. The most popular terrain representation, by far, used by modern real-time graphics applications is a regular 2D grid where the vertices are displaced in a third dimension by a displacement map, conventionally called a height map. It is the simplest and fastest possible terrain representation, but it is not possible to represent complex terrain models that include interesting terrain features such as caves, overhangs, cliffs and arches using a simple 2D grid and a height map. We propose a novel terrain representation combining the voxel and height map approaches that is expressive enough to allow creating complex terrains with caves, overhangs, cliffs and arches, and efficient enough to allow terrain editing, deformations and rendering in real-time. We also explore how to apply lighting, texturing, shadowing and level-of-detail to the proposed terrain representation.
Open Access
A shape grammar model for Anatolian madrasah architecture
(1999) Tekin, Senem
This thesis explores the role and potential of computational tools in the analysis of an existing corpus of work and synthesis of new designs. The research would like to demonstrate that, the basic grammar rules underlying the composition can be described by analyzing a set of similar designs, and new designs can be derived based on the extracted rules. Examples of Anatolian madrasahs from Anatolian region of Turkey have been chosen as a research corpus. The body of research is limited to Anatolian madrasahs that were built in the period of XII and XIII centuries having morphological similarities. After an initial evaluation of the material gathered from Kuran (1969) and Sozen (1970, 1972), in the first step, common features in plan composition are described within a research body. A classification for the plan types of the madrasahs is established. The location of main components like court, iwan(s), and other rooms are a major factor at the classification stage. The next step is the introduction of a shape grammar system for generating the plan layouts of Anatolian madrasahs through a number of rules by using the main plan components and their spatial relations. In the final step, a simple interpreter is developed by using the programming language AutoLisp for the representation of the shape grammar system for Anatolian madrasahs. The shape grammar system is realized in computer-aided design (CAD) environment to present an automated mechanism for generating different designs of Anatolian madrasahs through these rules. Such computational tools provide easy and flexible manipulation of objects so that many compositions can be created.
Open Access
Virtual sculpting with advanced gestural interface
(2013) Kılıboz, Nurettin Çağrı
In this study, we propose a virtual reality application that can be utilized to design preliminary/conceptual models similar to real world clay sculpting. The proposed system makes use of the innovative gestural interface that enhances the experience of the human-computer interaction. The gestural interface employs advanced motion capture hardware namely data gloves and six-degrees-of-freedom position tracker instead of classical input devices like keyboard or mouse. The design process takes place in the virtual environment that contains volumetric deformable model, design tools and a virtual hand that is driven by the data glove and the tracker. The users manipulate the design tools and the deformable model via the virtual hand. The deformation on the model is done by stuffing or carving material (voxels) in or out of the model with the help of the tools or directly by the virtual hand. The virtual sculpting system also includes volumetric force feedback indicator that provides visual aid. We also offer a mouse like interaction approach in which the users can still interact with conventional graphical user interface items such as buttons with the data glove and tracker. The users can also control the application with gestural commands thanks to our real time trajectory based dynamic gesture recognition algorithm. The gesture recognition technique exploits a fast learning mechanism that does not require extensive training data to teach gestures to the system. For recognition, gestures are represented as an ordered sequence of directional movements in 2D. In the learning phase, sample gesture data is filtered and processed to create gesture recognizers, which are basically finite-state machine sequence recognizers. We achieve real time gesture recognition by these recognizers without needing to specify gesture start and end points. The results of the conducted user study show that the proposed method is very promising in terms of gesture detection and recognition performance (73% accuracy) in a stream of motion. Additionally, the assessment of the user attitude survey denotes that the gestural interface is very useful and satisfactory. One of the novel parts of the proposed approach is that it gives users the freedom to create gesture commands according to their preferences for selected tasks. Thus, the presented gesture recognition approach makes the human-computer interaction process more intuitive and user specific.