Problems of Creation and Usage of 3D Model of Structures and Theirs Possible Solution

This article describes problems that occur when creating three-dimensional (3D) building models. The first problem is geometric accuracy; the next is the quality of visualization of the resulting model. The main cause of this situation is that current Computer-Aided Design (CAD) software does not have sufficient means to precision mapping the measured data of a given object in field. Therefore the process of 3D model creation is mainly a relatively high proportion of manual work when connecting individual points, approximating curves and surfaces, or laying textures on surfaces. In some cases, it is necessary to generalize the model in the CAD system, which degrades the accuracy and quality of field data. The article analyzes these problems and then recommends several variants for their solution. There are described two basic methods: using topological codes in the list of coordinates points and creating new special CAD features while using Python scripts. These problems are demonstrated on examples of 3D models in practice. These are mainly historical buildings in different locations and different designs (brick or wooden structures). These are four sacral buildings in the Czech Republic (CR): the church of saints Johns of Brno-Bystrc, the Church of St. Paraskiva in Blansko, further the Strejc’s Church in Židlochovice, and Church of St. Peter in Alcantara in Karviná city. All of the buildings were geodetically surveyed by terrestrial method while using total station. The 3D model was created in both cases in the program AUTOCAD v. 18 and MicroStation.

Innovative Educational Technology for the Use of Modern CAD Systems for the Formation of Professional Competences of Students of Radio Engineering Specialties

The basic principles of application of innovative educational technology on the basis of modern systems of automated design for higher educational institutions for students of radio engineering specialties are considered. Methods of forming competences in students for independent use of automated design systems in simulation of complex elements of autonomous information and control systems are shown. Features of modern CAD systems such as PTC Creo Parametric and Altair FEKO are described for their opportunities in teaching process in technical university. The results of simulation and calculations obtained by students during their individual tasks are given. 3D-models of microwave devices developed by students are discussed for formation of competences in electromagnetic simulation by numerical methods in special CAD systems. Especially, aspects of relationship between capabilities of students to create 3D-models and to calculate current distribution in microwave systems are discussed.

Parametric Programming of CNC Machine Tools

CNC machine tools are increasingly often used in industry, and the development of the methods of their programming is also proceeding. Modern multipurpose multi-axial machine tools are programmed using special CAD/CAM software programs. Universal special programs for controlling CNC machine tools can, however, be generated in programs written in high-level languages. An example can be the machining of gears on universal CNC machine tools using versatile machining tools.

A CAD/CAM System for Integrated Process of CNC Incremental Forming and 5-Axis Laser Cutting

The sheet metal forming is widely used in aerospace, automobile and shipbuilding industry. CNC incremental forming is a kind of recently developed flexible and dieless forming technology. This paper introduce an integrated process of CNC incremental forming and 5-axis laser cutting based on machining features, and the structure of related special CAD/CAM system as well as its development methods.

Study on CAD System of Centrifugal Fan

The paper develops a special CAD system for the centrifugal fan. The system can realize the automatic selection,aerodynamic design calculation,main parts parameterized drawing and other functions of the fan. It avoids the repetition of the manual labor and enhances the working efficiency and the cartography quality. On the base of the research on the selecting method and regularity of the main parameters of a large number of existing high performance centrifugal fans, the paper provides a new method, which determines the main geometric parameters of centrifugal impeller.

Research on Electrode Wear Prediction and Compensation On-Line Technology for Micro EDM Application

A micro-EDM equipment which can fabricate three-dimensional micro-structures is developed. A method of electrode wear compensation on-line which is very important to micro 3D structures machined by micro-EDM is presented. In this method, the wear of electrode can be predicted by the statistics law of open rate of discharge status, therefore, its precise model which is very difficult to build as well as the special CAD/CAM system is hardly necessary. At the same time, the micro-EDM CAD/CAM technology which applies the universal CAD/CAM software for milling is also researched and experienced on Unigraphics (UG). At last, micro 3D structures, a micro hemisphere with diameter ∅150+m and a micro 3D beam which is very popular in MEMS, are machined on silicon wafer by this way, which proves the wide useful of this method and the promising application in MEMS.