Analysis of Polygonal Computer Model Parameters and Influence on Fabric Drape Simulation

Contemporary CAD systems enable 3D clothing simulation for the purpose of predicting the appearance and behavior of conventional and intelligent clothing in real conditions. The physical and mechanical properties of the fabric and the simulation parameters play an important role in this issue. The paper presents an analysis of the parameters of the polygonal computer model that affect fabric drape simulation. Experimental research on physical and mechanical properties were performed for nine fabrics. For this purpose, the values of the parameters for the tensile, bending, shear, and compression properties were determined at low loads, while the complex deformations were analyzed using Cusick drape meter devices. The fabric drape simulations were performed using the 2D/3D CAD system for a computer clothing design on a disk model, corresponding to real testing on the drape tester in order to allow a correlation analysis between the values of drape parameters of the simulated fabrics and the realistically measured values for each fabric. Each fabric was simulated as a polygonal model with a variable related to the side length of the polygon to analyze the influence of the polygon size, i.e., mesh density, on the model behavior in the simulation. Based on the simulated fabric drape shape, the values of the areas within the curves necessary to calculate the drape coefficients of the simulated fabrics were determined in the program for 3D modelling. The results were statistically processed and correlations between the values of the drape coefficients and the optimal parameters for simulating certain physical and mechanical properties of the fabric were determined. The results showed that the mesh density of the polygonal model is an important parameter for the simulation results.

Spatial function of light in staging of contemporary choreography

The principles of using light in choreographic performances are the basis of image perception integrity. The novelty of the study is determined by the fact that the illumination as a component of the performance can be based not only on the physical laws of light, but also on its imitation. To look into the matter of illumination, the authors consider it necessary to use a polygonal model, which can also form a spatial picture if necessary. The paper defines the general illumination model, which uses ray tracing technology and allows to determine the structure of lighting in the hall and to distribute the light to understand the director's intention among the entire visual sector. The practical significance of the study is determined by the structure of using lighting as part of staging choreography in the postmodern genre.

A Polygonal Model to Design and Fabricate Ion-Exchanged Diffraction Gratings

We propose a simple polygonal model to describe the phase profile of ion-exchanged gratings. This model enables the design of these gratings, as well as the characterization of the ion-exchange process itself. Several ion-exchanged gratings were fabricated to validate the model and to characterize the process involved in their fabrication. From this characterization, we show the practical utility of the model by designing and fabricating both a grating that removes the zero order and a three splitter. The performance of these two elements was good, although the first one stood out especially because only 0.5% of the power remained in the zero order after diffraction. This polygonal model could be useful to design more complex diffractive elements.

A Comparative Study about Data Structures Used for Efficient Management of Voxelised Full-Waveform Airborne LiDAR Data during 3D Polygonal Model Creation

In this paper, we investigate the performance of six data structures for managing voxelised full-waveform airborne LiDAR data during 3D polygonal model creation. While full-waveform LiDAR data has been available for over a decade, extraction of peak points is the most widely used approach of interpreting them. The increased information stored within the waveform data makes interpretation and handling difficult. It is, therefore, important to research which data structures are more appropriate for storing and interpreting the data. In this paper, we investigate the performance of six data structures while voxelising and interpreting full-waveform LiDAR data for 3D polygonal model creation. The data structures are tested in terms of time efficiency and memory consumption during run-time and are the following: (1) 1D-Array that guarantees coherent memory allocation, (2) Voxel Hashing, which uses a hash table for storing the intensity values (3) Octree (4) Integral Volumes that allows finding the sum of any cuboid area in constant time, (5) Octree Max/Min, which is an upgraded octree and (6) Integral Octree, which is proposed here and it is an attempt to combine the benefits of octrees and Integral Volumes. In this paper, it is shown that Integral Volumes is the more time efficient data structure but it requires the most memory allocation. Furthermore, 1D-Array and Integral Volumes require the allocation of coherent space in memory including the empty voxels, while Voxel Hashing and the octree related data structures do not require to allocate memory for empty voxels. These data structures, therefore, and as shown in the test conducted, allocate less memory. To sum up, there is a need to investigate how the LiDAR data are stored in memory. Each tested data structure has different benefits and downsides; therefore, each application should be examined individually.

ANIMATED THREE-DIMENSIONAL MODEL OF THE AMUR COSSACK OF THE XVII CENTURY

The stages of modeling a historically accurate character are considered, from recreating the human body and clothing from sketches to optimizing and baking a highly polygonal model onto a texture.

Algorithms for Working with Orthogonal Polyhedrons in Solving Cutting and Packing Problems

In this paper problems of cutting and packing objects of complex geometric shapes are considered. To solve these NP-hard problems, it is proposed to use an approach based on geometric transformation of polygonal objects to composite objects (orthogonal polyhedrons) made up of rectangles or parallelepipeds of a given dimension. To describe the free space inside a voxelized container, a model of potential containers is used as the basic model that provides the ability of packing orthogonal polyhedrons. A number of specialized algorithms are developed to work with orthogonal polyhedrons including: algorithms for placing and removing composite objects, an algorithm for forming a packing with a given distance between objects to be placed. Two algorithms for the placement of orthogonal polyhedrons are developed and their efficiency is investigated. An algorithm for obtaining a container of complex shape presented as an orthogonal polyhedron based on a polygonal model is given. The article contains examples of placement schemes obtained by the developed algorithms for solving problems of packing two-dimensional and three-dimensional non-rectangular composite objects.

FRACTAL SURFACE INTERPOLATION BASED ON CLASSICAL SUBDIVISION SCHEMES

A method to create a differentiable complex shapes from simple polygonal models is proposed. It is shown that classical schemes of “smooth” subdivision can be obtained from local self-similarity ratios if “deflection arrows” are scaled as s2, where s is the linear compression coefficient calculated for a flat regular grid of the same structure. The surfaces obtained by a smooth subdivision do not contain sharp features other than the vertices and edges of the original model, so in order to create a surface of more exotic shape one must use more complex model. The article describes an alternative approach, in which a fractal forecast of the position of embedded vertices, calculated using the local geometric self-similarity ratio, is used to obtain a pronounced surface shape. Fractal forecast transfers the properties of the original polygonal model to a smaller scale, thereby generating secondary sharp surface features that compose a large-scale texture. To ensure the differentiability of the surface, the fractal forecast is combined with the “smooth” one, and the proportion of the latter increases with decreasing scale.

Simulation of the preparation and face drilling processes with laser scanning and automated marking of the drilling grid

The article discusses the methods of calculating the drilling and blasting scheme and constructing a drilling grid, manual and automatic calculation options are compared. A method for automatically constructing a drilling grid based on laser scanning is proposed. Moreover, the proposed method can be implemented using cheap equipment - a laser rangefinder and an Arduino microcomputer. Based on the data of the laser rangefinder with openCV and SciPy libraries, a polygonal 3D model of the face is built. The transfer of the drilling grid to the 3D model is implemented using the bilinear interpolation algorithm. The constructed polygonal model can be improved by making changes to the construction algorithm, since it is developed by the authors and can be further developed. The simulation model is created in Anylogic software and shows the drilling process taking into account the previously calculated drilling pattern. The proposed models can be used as a basis for further research and software development.

Reverse modeling of the human mandible 3D geometric model

Background/Aim. The geometry of each bone in the human skeletal system is unique. The aim of this research was to present application of a new method, method of anatomical features (MAF), for the creation of the geometrical model (surface and solid) of the human mandible. Methods. The method was based on Referential Geometrical Entities (RGEs) which have been defined on mandible polygonal model in accordance with anatomical properties of the mandible. Polygonal model was created over the input data (anatomical landmarks of the mandible) acquired from computed tomography scans. For the creation of computer-aided design (CAD) models in CATIA software, referential geometrical entities were defined according to the bone geometry and morphology features. Results. Definition of B-spline curves was performed on the body and on the ramus of the mandible. In this way, it was possible to create the geometrically accurate and anatomically correct three-dimensional geometric (surface and solid) models. The accuracy of the obtained surface model was tested through comparison with the geometry of the original bone model. Conclusion. Compared to the previously applied methods for creating geometric models, MAF provides more satisfactory results, and in some cases even better.

Developing 3D–models for training facilities of a space complex

The paper discusses problem statement for and software implementation of a Graphic Package Adaptation System (GPAS) intended for reading and processing graphic design data, produced by the CAD system PTC Creo. The idea is to introduce into the process of building a 3-D model of a spacecraft for training facilities an additional operation of ‘automated adaptation of the graphic package’. The proposed process does not exclude manual refinement of the model, however, including additional automated components into the process makes it possible to significantly reduce human effort required to build a model for training facilities. The exchange of models between PTC Creo, GPAS and Autodesk 3ds Max is conducted at the level of the open format Virtual Reality Modeling Language (VRML). The paper describes GPAS architecture, provides views of work windows of the program, and methods of running its main functions. Key words: Digital design model, polygonal model, simplification, graphic design data.