Field Of Computer-aided Design Research Articles

Auxetic dihedral Escher tessellations

The auxetic structure demonstrates an unconventional deployable mechanism, expanding in transverse directions while being stretched longitudinally (exhibiting a negative Poisson’s ratio). This characteristic offers advantages in diverse fields such as structural engineering, flexible electronics, and medicine. The rotating (semi-)rigid structure, as a typical auxetic structure, has been introduced into the field of computer-aided design because of its well-defined motion patterns. These structures find application as deployable structures in various endeavors aiming to approximate and rapidly fabricate doubly-curved surfaces, thereby mitigating the challenges associated with their production and transportation. Nevertheless, prior designs relying on basic geometric elements primarily concentrate on exploring the inherent nature of the structure and often lack aesthetic appeal. To address this limitation, we propose a novel design and generation method inspired by dihedral Escher tessellations. By introducing a new metric function, we achieve efficient evaluation of shape deployability as well as filtering of tessellations, followed by a two-step deformation and edge-deployability optimization process to ensure compliance with deployability constraints while preserving semantic meanings. Furthermore, we optimize the shape through physical simulation to guarantee deployability in actual manufacturing and control Poisson’s ratio to a certain extent. Our method yields structures that are both semantically meaningful and aesthetically pleasing, showcasing promising potential for auxetic applications.

Brep2Seq: a dataset and hierarchical deep learning network for reconstruction and generation of computer-aided design models

Abstract Three-dimensional (3D) reconstruction is a significant research topic in the field of computer-aided design (CAD), which is used to recover editable CAD models from original shapes, including point clouds, voxels, meshes, and boundary representations (B-rep). Recently, there has been considerable research interest in deep model generation due to the increasing potential of deep learning methods. To address the challenges of 3D reconstruction and generation, we propose Brep2Seq, a novel deep neural network designed to transform the B-rep model into a sequence of editable parametrized feature-based modeling operations comprising principal primitives and detailed features. Brep2Seq employs an encoder-decoder architecture based on the transformer, leveraging geometry and topological information within B-rep models to extract the feature representation of the original 3D shape. Due to its hierarchical network architecture and training strategy, Brep2Seq achieved improved model reconstruction and controllable model generation by distinguishing between the primary shape and detailed features of CAD models. To train Brep2Seq, a large-scale dataset comprising 1 million CAD designs is established through an automatic geometry synthesis method. Extensive experiments on both DeepCAD and Fusion 360 datasets demonstrate the effectiveness of Brep2Seq, and show its applicability to simple mechanical components in real-world scenarios. We further apply Brep2Seq to various downstream applications, including point cloud reconstruction, model interpolation, shape constraint generation, and CAD feature recognition.

Elegance in Pixels: Current Trends in Computer-aided Ornament Design

Current trends in the field of computer-aided design of ornaments are considered, as well as trends in changes in the perception of ornaments and the creation of decorative elements. It is noted that one of the trends is the fusion of traditions and innovations. Creative rethinking of age-old traditions in ornamentation is taking place today based on the use of modern computer technologies. The development of the field of parametric design, the use of algorithms and mathematical equations to create complex, intricate patterns and structures leads to the emergence of qualitatively new patterns that cannot be repeated by hand. The advent of 3D printing and additive manufacturing has revolutionized the creation of jewelry, and it has become possible to physically implement digital designs. Rapidly developing neural networks like Midjourney, Playground AI, DiffusionBee, DALL-E 2, Fy! Studio, etc. allow you to generate objects and use them as innovative sources of creative inspiration. The article provides examples of idea generation proposed by the authors in several neural networks. The world of ornamental design is experiencing a digital renaissance driven by the integration of technology and creativity. Through the fusion of tradition and innovation, parametric design, 3D printing, generative design and a commitment to sustainability, computer-aided ornament design is blossoming like never before. Thus, computer-aided design of patterns has turned fashion into a dynamic and innovative field where tradition meets technology. There are new opportunities for designer creativity, sustainability, and personalization of fashion. As digital age technology evolves, we can expect to continue to shape new ways of making clothes and expressing our-selves creatively.

Simple and Robust Boolean Operations for Triangulated Surfaces

Boolean operations on geometric models are important in numerical simulation and serve as essential tools in the fields of computer-aided design and computer graphics. The accuracy of these operations is heavily influenced by finite precision arithmetic, a commonly employed technique in geometric calculations, which introduces numerical approximations. To ensure robustness in Boolean operations, numerical methods relying on rational numbers or geometric predicates have been developed. These methods circumvent the accumulation of rounding errors during computation, thus preserving accuracy. Nonetheless, it is worth noting that these approaches often entail more intricate operation rules and data structures, consequently leading to longer computation times. In this paper, we present a straightforward and robust method for performing Boolean operations on both closed and open triangulated surfaces. Our approach aims to eliminate errors caused by floating-point operations by relying solely on entity indexing operations, without the need for coordinate computation. By doing so, we ensure the robustness required for Boolean operations. Our method consists of two main stages: (1) Firstly, candidate triangle intersection pairs are identified using an octree data structure, and then parallel algorithms are employed to compute the intersection lines for all pairs of triangles. (2) Secondly, closed or open intersection rings, sub-surfaces, and sub-blocks are formed, which is achieved entirely by cleaning and updating the mesh topology without geometric solid coordinate computation. Furthermore, we propose a novel method based on entity indexing to differentiate between the union, subtraction, and intersection of Boolean operation results, rather than relying on inner and outer classification. We validate the effectiveness of our method through various types of Boolean operations on triangulated surfaces.

Interview With Prof. Sung-Mo (Steve) Kang

Nicola Nicolici: Good afternoon. Let me welcome Prof. Kang from the University of California at Santa Cruz (UC Santa Cruz). Prof. Kang is an electrical engineer, scientist, professor, author, inventor, and entrepreneur. Currently, he is a distinguished professor emeritus at UC Santa Cruz. He has contributed extensively to the fields of computer-aided design for electronic circuits and systems. He holds 15 U.S. patents, has published over 500 articles, and has won numerous awards for his achievements. He has led the development of the world’s first 32-bit microprocessor chip, Bellmac-32, as a technical supervisor at ATT Bell Labs, Murray Hill, NJ, USA, and has designed satellite-based private communication networks as a member of technical staff.

The Shape Analysis of DTB-like and DT B-spline-like Curves

In the field of computer-aided design and related applications, the free curve with parameters shows its strong function. But an excellent curve with parameters need to eliminate unnecessary cusps and inflection points, so shape analysis is needed for some specific curves. We have already shown many excellent properties of the DTB-like curves and DT B-spline-like curves. Thus the shape features like convexity, loops, inflection points, and cusps of the DTB-like curves, and DT B-spline-like curves are further discussed in this paper. And the necessary and sufficient conditions for the existence of shape features of the corresponding DTB-like curves and DT B-spline-like curves are given. And the shape features distribution all be generalized into tables and diagrams, which are useful for industrial design. In addition, the effect of shape parameters on the shape features diagram and its adjustment ability to the shape of corresponding curves are analyzed, respectively. The work in this paper enables users to determine how to set parameter values so that the generated curve could be a global convex or local convex curve, has a required inflection point, or eliminate the unnecessary one, and could be adjusted to another aimed shape.

Almost-[formula omitted] splines: Biquadratic splines on unstructured quadrilateral meshes and their application to fourth order problems

Isogeometric Analysis generalizes classical finite element analysis and intends to integrate it with the field of Computer-Aided Design. A central problem in achieving this objective is the reconstruction of analysis-suitable models from Computer-Aided Design models, which is in general a non-trivial and time-consuming task. In this article, we present a novel spline construction, that enables model reconstruction as well as simulation of high-order PDEs on the reconstructed models. The proposed almost-C1splines are biquadratic splines on fully unstructured quadrilateral meshes (without restrictions on placements or number of extraordinary vertices). They are C1 smooth at all regular and extraordinary vertices. Moreover, they are C1 smooth across all edges between regular vertices and C0 smooth across all edges that are adjacent to an extraordinary vertex. The splines thus form H2-nonconforming analysis-suitable discretization spaces. This is the lowest-degree unstructured spline construction that can be used to solve fourth-order problems. The associated spline basis is non-singular and has several B-spline-like properties (e.g., partition of unity, non-negativity, local support), the almost-C1 splines are described in an explicit Bézier-extraction-based framework that can be easily implemented. Numerical tests suggest that the basis is well-conditioned and exhibits optimal approximation behaviour.

Shape classification based on solid angles by a support vector machine

In the field of computer-aided design (CAD) and three-dimensional (3D) modeling, constructive solid geometry (CSG) representations based on primitive 3D shapes and boundary representations (B-Rep) based on geometry and topology are widely used to represent complex shapes. Therefore, it is important to recognize primitive shapes such as cubes, cones, and cylinders and to accurately judge and classify the deformation of primitive shapes. For this purpose, various techniques have been studied, such as a vector-based determination method, a determination method using multiple images from various angles, and a determination method based on positional relationships between points. However, because large datasets are required to classify these shapes and it is difficult to respond to changes in shape due to rotation, the resulting recognition accuracy is not always high. In this work, we propose a method based on solid angles, which do not depend on the positional relationship of vectors, viewpoints, or changes due to rotation, as feature quantities. We demonstrate the effectiveness of primitive 3D figures using features based on solid angles. In addition, we show that the presence or absence of deformation can be determined when part of a primitive 3D figure is deformed.

Review of Subdivision Schemes and their Applications

Background: Methods of subdivision surfaces modeling and related technology research have become a hot spot in the field of Computer-Aided Design (CAD) and Computer Graphics (CG). In the early stage, research on subdivision curves and surfaces mainly focused on the relationship between the points, thereby failing to satisfy the requirements of all geometric modeling. Considering many geometric constraints is necessary to construct subdivision curves and surfaces for achieving high-quality geometric modeling. Objective: This paper aims to summarize various subdivision schemes of subdivision curves and surfaces, particularly in geometric constraints, such as points and normals. The findings help scholars to grasp the current research status of subdivision curves and surfaces better and explore their applications in geometric modeling. Methods: This paper reviews the theory and applications of subdivision schemes from four aspects. We first discuss the background and key concept of subdivision schemes and then summarize the classification of classical subdivision schemes. Next, we review the subdivision surfaces fitting and summarize new subdivision schemes under geometric constraints. Applications of subdivision surfaces are also discussed. Finally, this paper provides a brief summary and future application prospects. Results: Many research papers and patents on subdivision schemes are classified in this review paper. Remarkable developments and improvements have been achieved in analytical computations and practical applications. Conclusion: Our review shows that subdivision curves and surfaces are widely used in geometric modeling. However, some topics need to be further studied. New subdivision schemes need to be presented to meet the requirements of new practical applications.

TO THE QUESTION OF COMPUTER PARAMETRIC DESIGN IN THE KOMPAS-3D SYSTEM

Computer-aided design is a highly productive means of improving the quality of technical products, reducing the cost of its development and operation. Geometric models are the basis for processing throughout the entire life cycle for complex object. Proper results significantly depend on their perfection.
 This special function is due to their leading role in the process of harmonizing the often controversial requirements of many technical and other disciplines to the designed industrial products. Its specific optimal variant is necessarily implemented by certain geometry. For effective search the latter, computer graphics models must provide not only the desired clarity and accuracy, but also the flexibility of modifications to the executed constructions. In this way, the created object is adapted to the existing various requirements for it.
 The modern implementation of the described strategy of automated design is a parametric approach to the development of industrial products. For its successful use in practice, it is necessary to pay appropriate attention to this topic when applicants for higher education study engineering graphics. Therefore, this direction is quite relevant.
 On the other hand, there are now theoretical developments that generalize the parametric geometric modeling. This applies, for example, the methodology of structural-parametric shaping, which was developed by the scientific school of applied geometry of the National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute". The above facts determine the appropriateness of acquainting students with new theoretical achievements in the field of computer-aided design, which will help improve their future professional activity.
 Thus, the main purpose of this publication is to present the proposed method to teaching computer design of industrial products in higher education institutions on the example of the Kompas-3D system. The described techniques are quite universal, they can also be used in other relevant software packages, in particular, AutoCAD, SolidWorks, CATIA, NX, ProEngineer etc.

GenFloor: Interactive generative space layout system via encoded tree graphs

Automated floorplanning or space layout planning has been a long-standing NP-hard problem in the field of computer-aided design, with applications in integrated circuits, architecture, urbanism, and operational research. In this paper, we introduce GenFloor, an interactive design system that takes geometrical, topological, and performance goals and constraints as input and provides optimized spatial design solutions as output. As part of our work, we propose three novel permutation methods for existing space layout graph representations, namely O-Tree and B∗-Tree representations. We implement our proposed floorplanning methods as a package for Dynamo, a visual programming tool, with a custom GUI and additional evaluation functionalities to facilitate designers in their generative design workflow. Furthermore, we illustrate the performance of GenFloor in two sets of case-study experiments for residential floorplanning tasks by (a) measuring the ability of the proposed system to find a known optimal solution, and (b) observing how the system can generate diverse floorplans while addressing given a constant residential design problem. Our results indicate that convergence to the global optimum is achieved while offering a diverse set of solutions of a residential floorplan corresponding to local optimums of the solution landscape.

CAD/CAM-based referencing aids to reduce preoperative radiation exposure for intraoperative navigation.

All intraoperative navigation systems need a referencing procedure prior to utilization, usually requiring an additional computed tomography (CT) or cone beam computed tomograph (CBCT) scan. As new techniques in the field of Computer-aided design / Computer-aided manufacturing (CAD/CAM) have evolved, it seemed favourable to develop a new referencing method not relying on additional CT or CBCT scans. A digital maxillary dental scan was used to create a referencing splint by CAD/CAM containing four reference points. By matching scanned dental model and initial trauma-CT, the splints position and thus the reference points were digitally simulated. These splints data were imported into the navigation system in Standard Tessellation Language (STL) format. These data were also 3D printed and the resulting piece was placed on the anatomical models' teeth. The methods accuracy was then assessed in vitro. Our method for referencing of intraoperative navigation can be feasible to avoid an additional CT or CBCT prior to navigation.

A Parallel Approach to Perform Threshold Value and Propagation Delay Analyses of Genetic Logic Circuit Models.

Experiments with synthetic genetic logic circuits can be time-consuming and expensive. Accordingly, advances in the field of computer-aided design and simulation of genetic circuits have reduced the cost and time required for experimentation. D-VASim is the first genetic circuit simulation tool that allows users to interact with the model during run-time. In contrast to electronic circuits, genetic circuits have different threshold values for different circuits, which need to be estimated prior to simulation. D-VASim allows the user to perform threshold concentration and propagation delay analysis before simulating the circuit. The algorithm currently used in D-VASim has considerable scope for improvements. Thus, we propose a parallel implementation of the algorithm, significantly faster by up to 16 times. In adddition, we improve the algorithm for consistent runtimes across multiple simulation runs under the same parameter settings, reducing the worst-case standard deviation in runtime from 6.637 to 1.841. Our algorithm also estimates the threshold value more accurately, as evident from experimentation for long runtimes. With these modifications, the utility of D-VASim as a virtual laboratory environment has been significantly enhanced.

Методи автоматизованого проектування гетерогенних комп’ютерних систем та мереж критичного застосування

The article provides a review of design methods for heterogeneous computer information systems and critical application networks, analyzes requirements, provides a description of information technologies, their components, conditions of use, results of their application. A method for the computer-aided design of heterogeneous computer systems and critical application networks is proposed when operational tasks are included in the control system. The analysis of features arising during reconfiguration is carried out. The modern basic technical and software of computer systems for critical applications are analyzed. The general requirements for computer systems of critical applications and their components are formulated. The development trends and existing needs of computer systems and networks of critical application are determined. Based on the analysis of heterogeneous computer networks and theoretical generalization of work in the field of computer-aided design of critical application systems, the authors have developed a method for the computer-aided design of heterogeneous computer systems and critical-use networks.

Autoencoder-based part clustering for part-in-whole retrieval of CAD models

Part-in-whole retrieval (PWR) is an important problem in the field of computer-aided design (CAD) with applications in design reuse, feature recognition and suppression and so on. Initially, we present a non-parametric (and hence threshold independent) algorithm for segmenting CAD models (represented as meshes) which does not require any user intervention. As there is no labelled segmented dataset available for part clustering, we propose the use of autoencoders, one of the approaches used in deep networks along with hierarchical clustering. The features for autoencoder is derived from the Gauss map of the segments. The autoencoder network is then trained and validated using a hierarchical clustering-based approach that generates a dictionary of labels for each segment. PWR is then done by testing a query model with the network that retrieves models having the query as their subset. Comparison of the segmentation algorithm with the state-of-the-art approaches indicate that it performs better or on par. The algorithm was also tested for noisy models. Results of the part clustering and PWR are also presented for models from a CAD dataset along with the discussions.

A closed-form general solution for the distance of point-to-ellipse in two dimensions

This paper resolved a closed-form general solution for the distance of one point and one ellipse in a two dimensional plane. Even such problem is simple as apparently to be understood, the solutions provided from literature are all about iterative algorithms or approximating approaches. None of O(1) methods or general roots solutions are found. The author takes several geometrical transformations to reduce the power of the equation to simplify the problem. Eventually, a closed-form general solution is resolved in this paper. This can be a contribution both for academic and for in practice and should be archived. Based on this general solution, we can develop the algorithm computing the shortest path touring n sequenced ellipses soon. Since the results of this paper is sufficiently fundamental, it can be conducted in a variety of applications: in the fields of computer-aided design and manufacturing, computer graphics, layered manufacturing, prototyping, robot motion (path) planning, wireless sensor networking, multimedia animation, geodesy, astronomy, physics, molecular geometry, electromagnetics, and Fluid mechanics.

Аспекты преподавания курса «мультимедийные технологии» на дизайнерских специальностях авиационных вузов

The way of the formation of competence in teaching the course "Multimedia Technology" for students majoring computer science - the designer. The choice of areas of teaching the course for the MT specialists design a bias in education. The basic thesis of the course for the MT specialty "Computer science in the field of computer-aided design" in the MAI.Presents practical techniques of the educational process on discipline.

АВТОМАТИЗАЦИЯ СТРУКТУРНО-ПАРАМЕТРИЧЕСКОГО АНАЛИЗА ПРОЕКТНЫХ РЕШЕНИЙ И ОБУЧЕНИЯ ПРОЕКТИРОВЩИКА ИЗДЕЛИЙ МАШИНОСТРОЕНИЯ СРЕДСТВАМИ САПР КОМПАС

The actual task in the field of computer-aided design of machine-building objects is to increase the level of automation of structural-parametric analysis of design solutions due to the repetition of their use, reducing the number of design operations and ensuring the corresponding competencies of designers. Developed methods and algorithms should ensure the acquisition of the necessary competencies for the designer for successful project activities in the field of computer-aided design, increasing the effectiveness of training. The system of analysis of design solutions should improve the quality of design solutions implemented in CAD KOMPAS-3D.
 In this paper, an overview of methods, systems and tools for analyzing design solutions implemented in the CAD-3D environment. The main features of such systems are described, their main disadvantages are identified: the lack of functions for determining non-optimal sequences of design operations, the inability to automatically rebuild a three-dimensional model of a machine-building product on the basis of analysis of the design model tree. A complex system for the analysis of project solutions and the training of a designer was developed and implemented, based on methods, models and algorithms for analysis and adaptive learning. The results of a computational experiment are presented, on the basis of which it can be concluded that the use of developed software enhances the efficiency and quality of the designer's training in the processes of constructing three-dimensional solid-state machine-building products in CAD KOMPAS-3D.

Ontological approach to the formation of subject-oriented knowledge bases in the field of computer-aided design

The problem of the formation of subject-oriented knowledge bases in the subject area of operation of computer-aided design systems is discussed. One of the trends in the development of CAD systems is their intellectualization through the development of a system-wide environment, including the means of methodological support of the design activities of users. It is proposed to use the otological approach in identifying and updating the content of knowledge bases used by target CAD personnel. The results of an experiment on the development of a targeted taxonomy in the subject area of computer-aided design of engineering products are presented.

Direct slicing of T-spline surfaces for additive manufacturing

PurposeT-spline is the latest powerful modeling tool in the field of computer-aided design. It has all the merits of non-uniform rational B-spline (NURBS) whilst resolving some flaws in it. This work applies T-spline surfaces to additive manufacturing (AM). Most current AM products are based on Stereolithograph models. It is a kind of discrete polyhedron model with huge amounts of data and some inherent defects. T-spline offers a better choice for the design and manufacture of complex models.Design/methodology/approachIn this paper, a direct slicing algorithm of T-spline surfaces for AM is proposed. Initially, a T-spline surface is designed in commercial software and saved as a T-spline mesh file. Then, a numerical method is used to directly calculate all the slicing points on the surface. To achieve higher manufacturing efficiency, an adaptive slicing algorithm is applied according to the geometrical properties of the T-spline surface.FindingsExperimental results indicate that this algorithm is effective and reliable. The quality of AM can be enhanced at both the designing and slicing stages.Originality/valueThe T-spline and direct slicing algorithm discussed here will be a powerful supplement to current technologies in AM.