Software technical drawing: a guide to CAD
CAD software is the application of computer technology to the design, particularly in technical drawing and engineering as part of a product, including entire buildings.
Overview
It 'a method of communication is visual, is based on symbols, and its conventions are particular to each specific technical field of application. The proofs can be made in two dimensions ("2D") and three-dimensional ("3D").
The realization of drafts is necessary for technical or engineering drawings and is a branch of industrial art behind all the technical achievements. To represent complex objects, three-dimensional, two-dimensional drawings in, these objects are traditionally represented through three projections at right angles.
Current CAD software packages range from systems design vector-based 2D to 3D solid and surface models. Modern CAD packages often allow rotations in three dimensions, allowing you to see a certain object from any angle, even from the inside. Some CAD software allow dynamic mathematical models, and in this case they are called CADD - computer-aided design and drafting.
CAD is used in the design of tools and machinery and for drafts of all types of buildings, from small residential homes to the largest commercial and industrial structures (hospitals and factories).
CAD is mainly used for detailed engineering models 3D and / or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and products, throughout the dynamic analysis of assemblies to definition of the methods of production of the components.
CAD has become a very important technology, with advantages such as low cost of product development cycles and design much faster. CAD allows designers to develop their ideas on screen, print and save for future editing, saving time on the drawings.
Technologies
The original software for CAD systems was developed with computer languages such as Fortran, but with the progress in methods of object-oriented programming, there have been great changes. The modern systems based modelers parametric functions and freeform surface are built around a number of key modules C (programming language) with their APIs. A CAD system can be seen as the result of the interaction of a graphical user interface (GUI) with NURBS geometry and / or boundary representation (B-rep) via a geometric modeling kernel.
E 'can also use a search engine to manage the associations between geometric data, such as wireframe geometry in a sketch or components in an assembly. The unexpected possibilities of these associations have led to a new form of construction of the prototypes, digital. Unlike physical prototypes, the production of which requires time and material costs, digital prototypes allow you to check and test the design directly on the screen, accelerating time to market and reducing costs. With the evolution of technology in this direction, CAD has been transformed from documentation tool (to represent the design in a graphical format) in the configuration tool that assists in the design process.
Hardware and technologies os
Today, the majority of computer CAD systems are Windows-based PCs. Some CAD systems also work on Linux and Unix operating systems. Some CAD systems such as CAD, you NX or CATIA V5-platform support including Windows, Linux, UNIX, and Mac OS X.
It is generally not required special hardware, with the possible exception of a good graphics card, depending on the CAD software used. However, for more complex products, are recommended computer with high-speed CPU (possibly multiple) and large amounts of RAM. CAD is an application that has benefited from the installation of a coprocessor, especially in the first personal computer. The device of man-machine interface is generally the mouse, but can also be a pen or a tablet. Sometimes you can also use a SpaceMouse / SpaceBall. Some systems also support stereoscopic glasses to see the 3D models.
Use
CAD is one of the tools used by engineers and designers, is used in many different ways depending on the user's profession and the type of software in question. There are many different types of CAD. Each of these types of CAD systems require the operator to think of the use which will make and requires a different production technique of virtual components. There are many manufacturers of 2D economic systems, including some free and open source programs. These offer an approach to the design process without all the issues related to scaling and positioning the accompanying drawing by hand, since they can be adapted during the creation of the final draft.
The 3D wireframe is an extension of the 2D drawing. Each line must be manually entered in the drawing. The final product has no mass properties associated and can not have the functions added directly. The operator approaches to these systems in a manner similar to 2D systems, although many 3D systems allow using the wireframe model for the final drafts.
3D solids "dumb" (programs incorporating this technology include AutoCAD and Cadkey 19) are made in a similar way to manipulation of real objects. Basic three-dimensional geometric forms (prisms, cylinders, spheres, and so on) have solid volumes that are added or subtracted, as is done for assembling or cutting real-world objects. Two-dimensional projected visuals can be easily generated by the models. The basic 3D solids do not usually include tools to easily allow their movement or identify interference between components.
The 3D parametric solid modeling (programs incorporating this technology include Pro / ENGINEER, NX, the combination of UniGraphics and IDEAS, CATIA V5, Autodesk Inventor, Alibre Design, TopSolid, T-FLEX CAD, SolidWorks, and Solid Edge) requires that the 'operator to use what is known as "design intent". The objects and features created are adjustable. Any future modifications will be simple, difficult or nearly impossible, depending on how you created the original.
You have to think of it as a perfect representation of a component. If a function must be localized at the center, the operator must locate the center of the model, not from another angle arbitrarily. The parametric solids require the operator to consider carefully the consequences of his actions. Some software packages allow you to edit parametric and non-geometric images, without the need to understand or undo the design of the figure using the direct modeling capabilities. This option could include the possibility of establishing the correct relationships between selected geometry (ie tangent lines, concentricity), which makes the editing process faster and easier, freeing the engineer from the burden of understanding the history of the model.
These types of systems not based on the history are called Explicit Modellers.
The first Explicit Modeling systems were introduced in the late 80s by Hewlett-Packard under the name SolidDesigner. This CAD solution, many of which were made later, is now sold by the PTC as "CoCreate Modeling." The draft preview can be generated easily from the models. They are usually present tool to represent the motion of components, set limits and identify interference. The tool kits available for these systems are becoming more numerous.
The mid-range software are integrating parametric solids in a more simple for the user: they offer more intuitive functions (SketchUp), using the best of 3D solids dumb and parametric solid (VectorWorks), allowing to obtain realistic scenes in a few steps (Cinema4D) or by offering all these functions in a (form • Z).
The most advanced systems have the ability to incorporate more organic characteristics, aesthetic and ergonomic in design (Catia, GenerativeComponents). The freeform surface modeling is often combined with solids to allow the designer to create products that adapt well to human forms as well as interface with the machine.
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Source:
Italian version of ReteArchitetti.it