OGS : a lightweight object-oriented graphics system for instruction

Existing graphics systems are too large for students to study in an introductory computer graphics course. We have implemented a lightweight, object-oriented graphics system called OGS for instruction. OGS is written in Java. It demonstrates how a graphics system is implemented from scratch and is intended to help students understand graphics algorithms at the source code level. OGS im­plements window-viewport coordinate transformation, projection, 3D transformation, hidden surface elimination, Lambert shading, Phong hading, Constructive Solid Geometry, and ray tracing. OGS is able to model specular highlight, shadow, reflection and transmission.Keywords and Phases: OGS, computer graphics, polygon mesh, ray tracin

Constructive geometry in implementations of modern 3D graphics

3D graphics are one of the crucial development trends of modern digital technologies. Engineering and manufacturing, architecture, design, cinematography, education, and the game industry are an incomplete list of industries where it is actively used. Specialists in 3D graphics are in high demand in the labor market. Their proper training presupposes high-quality knowledge of geometrical sciences, in particular – constructive geometry. Note that constructive geometry is an integral part of modern school mathematics education. That is why, even in the conditions of the school, the teacher should skillfully apply the demonstration capabilities of three-dimensional graphics. It will also encourage students of a comprehensive school to apply knowledge of constructive geometry in practice in the area of 3D modeling. This approach will make it possible to demonstrate the importance and interconnectedness of knowledge in geometry and computer science. Therefore, the article reveals the importance of interdisciplinary connections between the specified disciplines in the context of research, demonstration, and application aspects. In particular, the nuances of using the GeoGebra dynamic geometry complex for conducting computational experiments and creating spatial models based on tasks from a school spatial geometry course are described. After all, modern capabilities of software tools make it possible to demonstrate in real time all the transformations that took place during drawing modeling on the picture plane. The importance of the applied value of constructive geometry for 3D modeling reveals based on examples of solid and polygonal modeling of virtual spatial objects. In particular, the steps of creating a solid model of a pyramid, which is formed by cutting it off with a plane from a regular quadrangular pyramid, are illustrated by the basis of calculations and constructions, which are performed using techniques of constructive geometry. All stages are described and done using the TinkerCAD online modeling service tools. An example of using the Blender program for creating polygonal 3D models is also provided. In particular, the significant aspects of the part modeling process are presented in the example of a task from a drawing textbook. The importance of planimetric constructions in the process of performing high-precision polygonal modeling is also emphasized. The article contains many figures that illustrate the essential stages of modeling. The materials presented can be used to prepare lessons in either mathematics or computer science and can be used to conduct integrated classes that draw on both subjects. Possible prospects for further research on this topic are also presented

Digitally interpreting traditional folk crafts

The cultural heritage preservation requires that objects persist throughout time to continue to communicate an intended meaning. The necessity of computer-based preservation and interpretation of traditional folk crafts is validated by the decreasing number of masters, fading technologies, and crafts losing economic ground. We present a long-term applied research project on the development of a mathematical basis, software tools, and technology for application of desktop or personal fabrication using compact, cheap, and environmentally friendly fabrication devices, including '3D printers', in traditional crafts. We illustrate the properties of this new modeling and fabrication system using several case studies involving the digital capture of traditional objects and craft patterns, which we also reuse in modern designs. The test application areas for the development are traditional crafts from different cultural backgrounds, namely Japanese lacquer ware and Norwegian carvings. Our project includes modeling existing artifacts, Web presentations of the models, automation of the models fabrication, and the experimental manufacturing of new designs and forms

TetSplat: Real-time Rendering and Volume Clipping of Large Unstructured Tetrahedral Meshes

We present a novel approach to interactive visualization and exploration of large unstructured tetrahedral meshes. These massive 3D meshes are used in mission-critical CFD and structural mechanics simulations, and typically sample multiple field values on several millions of unstructured grid points. Our method relies on the pre-processing of the tetrahedral mesh to partition it into non-convex boundaries and internal fragments that are subsequently encoded into compressed multi-resolution data representations. These compact hierarchical data structures are then adaptively rendered and probed in real-time on a commodity PC. Our point-based rendering algorithm, which is inspired by QSplat, employs a simple but highly efficient splatting technique that guarantees interactive frame-rates regardless of the size of the input mesh and the available rendering hardware. It furthermore allows for real-time probing of the volumetric data-set through constructive solid geometry operations as well as interactive editing of color transfer functions for an arbitrary number of field values. Thus, the presented visualization technique allows end-users for the first time to interactively render and explore very large unstructured tetrahedral meshes on relatively inexpensive hardware