AutoCAD, one of the most popular drawing programs, has enriched over time the facilities offered in making drawings in terms of how to use different graphics, symbols, accuracy, speed, interface, ...etc. One aspect that gives it an advantage over other drawing programs is the ability to use the AutoLisp language in creating user’s functions that can be used as commands in AutoCAD. In this article, the authors present a function made in AutoLisp, which, for the parts drawn in Autocad, facilitates the automatic dimensioning of the chamfers, in the usual format, considering the scale of the respective drawing or detail.
In production areas dedicated to the manufacturing of small series or unique products, i.e. in sectors which require frequent calculations for geometric determinations (such as the case of obtaining ...the unfolded shape of oblique cones frustums from the joints of different tubes (pipes) of varying diameters and/or orientations it is useful to achieve their development within a short timeframe, accurately and with minimal effort. ...there will be enough elements to facilitate the drawing of the unfolded shape (Figure 1). The advantages of this function are represented by the following featmes: it presents the possibility to unfold the conical surface in two ways - starting from the minimum length of the slant height or from the maximum length (fact that has an impact on the manufacturing process in optimizing the consumption of material used); the high precision of the unfolding is controlled by the user depending on the technological limitations; the function collects its own calculation data solely through the user's accurate indication of the graphic elements of the cone; it can be run directly in the current session without leaving the work enviromnent. In cases where the truncated cone or the cone itself is obtained from a single piece of material joined on a single side (slant heights), because the function offers the possibility of choosing the side with which to start unfolding (by indicating the larger or smaller portion of the slant height of the cone frustum), the material consumption can be optimized depending on the resulting geometry and the dimensions of the existing half-finished product (Figure 3).
The article is devoted to modeling and visualization of the formation of flat-nosed (snub-nosed) dodecahedron (snub dodecahedron). The purpose of the research is to model the snub dodecahedron ...(flat-nosed dodecahedron) and visualize the process of its formation. The formation of the faces of the flat-nosed dodecahedron consists in the truncation of the edges and vertices of the Platonic dodecahedron with the subsequent rotation of the new faces around their centers. The values of the truncation of the dodecahedron edges, the angle of rotation of the faces and the length of the edge of the flat-nosed dodecahedron are the parameters of three equations composed as the distances between the vertices of triangles located between the faces of the snub dodecahedron. The solution of these equations was carried out by the method of successive approximations. The results of the calculations were used to create an electronic model of the flat-nosed dodecahedron and visualize its formation. The task was generally achieved in the AutoCAD system using programs in the AutoLISP language. Software has been created for calculating the parameters of modeling a snub dodecahedron and visualizing its formation.
Placement of the dimension in relation to the dimension line, depending on its orientation. 2.2 Explanation of the concept When launching the command (function) for dimensioning of the chamfer, you ...will be asked to indicate the edge resulting from the bevel operation. To calculate the distance at which the bevel is made, the scale factor characteristic of the current dimensioning style used to dimension the bevel shall be included in the calculation formula. Depending on this value, the width of the font is determined and finally the length of the dimension line is calculated, maintaining a reserve of space, symmetrically distributed at both ends of the dimension line. If an entity of the type mentioned above is not indicated, it is required to enter the respective edge until the correct selection of a LINE type entity or until the exit from the command by pressing the Enter or Escape key (Figure 2). 3 THEORETICAL BASES OF CALCULATION Calculation elements from analytical geometry are used 1. Since the coordinates of the points of the ends of the segments that are used for the calculation of the chamfer can be collected, we start from the following analytical formulas. - (5) 4 LISTING OF THE SOFTWARE Below is the listing of the software that generated the DIMCH function: 5 CONCLUSIONS Given that the dimensioning of chamfers function (DIMCH) has solved the issues mentioned at the beginning of the article, it can be said that it has achieved its purpose for which it was created: saving time (by reducing orders or data entered), ease of use (easy launch, suggestive queries), increase accuracy (PC calculations), reduce human error (is used the same scaling factor used for the dimensioning style used).
The most common method of forming semi-control polyhedra consists in cutting off angles and ribs of regular polyhedra by planes. The aim of the work - to consider the automated formation of a number ...of surfaces of semi-regular Archimedean polyhedra based on the dodecahedron. These include the truncated dodecahedron, the icosododecahedron, the romboicosododecahedron and the truncated icosododecahedron. The formation of surfaces is carried out by the kinematic method in AutoCAD using programs compiled in the AutoLISP language. Methods. The methodology for the formation of these polyhedra provides for truncation of the angles and edges of the dodecahedron. This requires the calculation of a number of geometric parameters of these polyhedra and dodecahedron, such as the value of the truncation of the dodecahedron edges, the size of the edges of truncated polyhedra, the centers of faces, dihedral angles, etc. In order to generate these surfaces, a frame is constructed because the frame lines are used as guides to form surfaces in a kinematic way. The electronic model of each polyhedron is constructed as a set of compartments of surfaces of all its faces, and each compartment is assigned to a certain layer of the drawing. The frame and electronic model of the polyhedra under study are formed by means of user programs composed in the functional language AutoLISP. The process of forming surfaces of selected polyhedra in the AutoCAD environment is provided by special programs that are also compiled in the AutoLISP language. Results. Software was created to demonstrate the process of formation of a number of Archimedes polyhedra on the monitor screen.
3D city models are a useful tool to analyze the solar potential of neighborhoods and cities. These models are built from buildings footprints and elevation measurements. Footprints are widely ...available, but elevation datasets remain expensive and time-consuming to acquire. Our hypothesis is that the GIS cadastral data can be used to build a 3D model automatically, so that generating complete cities 3D models can be done in a short time with already available data. We propose a method for the automatic construction of 3D models of cities and neighborhoods from 2D cadastral data and study their usefulness for solar analysis by comparing the results with those from a hand-built model. The results show that the accuracy in evaluating solar access on pedestrian areas and solar potential on rooftops with the automatic method is close to that from the hand-built model with slight differences of 3.4% and 2.2%, respectively. On the other hand, time saving with the automatic models is significant. A neighborhood of 400,000 m2 can be built up in 30 min, 50 times faster than by hand, and an entire city of 967 km2 can be built in 8.5 h.
In this study, the polar equations and complex numbers of curves are used to design elliptical gears that require machine tools that are difficult to produce by conventional methods and require ...special consultation. Using these equations, a package program has been developed by using AtuoLISP programming language in order to realize the desired number of teeth and design of elliptical gears in AutoCAD environment.ss With this package program, elliptical gear design has been realized in 5 different modules and number of teeth and they have been manufactured in CNC Wire EMD. The most important parameter for analyzing the workability of elliptical gears is the distance changes between axes. In order to analyze this experimentally, an elliptical gear analysis mechanism is designed and manufactured. In this study, a pair of elliptical gear driven crank connecting bar mechanism and four bar mechanism were analyzed. In addition, the distribution of tooth stress using the Cosmosworks module of the Solidworks program and frequency analysis using the ANSYS program were performed. The results of this study exhibitioned that elliptical gears can be used in many industrial applications.
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