What are the disadvantages of CAD

CAD - Computer Aided Design

CAD means computer aided design and is translated into German as computer-aided design translated. This is used to create products using a computer and software. In the meantime, this is mainly happening in the third dimension (3D Parts / 3D Products).

The big advantage is the spatial representation of the products. This can be used to quickly create spatial images that are more suitable as a basis for discussion than complex 2D drawings. Furthermore, the three-dimensional data can be made available directly for use in production (example 3D printing).

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Basics of CAD technology

2D CAD

In 2D CAD, basic objects such as straight lines, circles, ellipses, polylines, polygons or splines become vector-oriented, two-dimensional object created. By dimensioning, labeling, selecting the color, the line type and the line width, all possibilities in 2D CAD could be dealt with in digital form that were previously done by hand on the drawing board.

The two-dimensional objects are described mathematically by vectors. In contrast to pixel graphics (jpg, png, gif) less memory is required.

The drawings can easily be created, edited or deleted. Dimensions are calculated automatically by the CAD program. Individual areas can be provided with hatching with one click.

The function for moving or zooming the 2D CAD drawing facilitates the creation of larger constructions. With the help of a plotter, the digital drawings can be put on paper. A plotter or curve recorder can print vector graphics (in this case technical drawings) directly without having to convert them into pixel graphics.

You can read about the advantages and disadvantages of 2D CAD systems here - Why companies should use 3D CAD.

2½ CAD

The 2½ CAD was the next step towards 3D CAD. Here will be Body indicated by lines in space. However, the body itself does not contain any mathematically described volume. Its interior and its surface are not determined.

2½D models are therefore wrong 3D models. They are also known as wireframes because of their appearance through lines and edges. 2½ CAD programs are no longer offered today. The development of 3D CAD has replaced this technology.

3D CAD

In 3D CAD, a virtual model of a three-dimensional object is created. In addition to the mathematical or geometric description of the body, it also has physical properties such as density or mechanical, optical and thermal properties. This is how a simple volume model becomes a realistic body model.

Due to the properties, the body can be weighed virtually in the 3D CAD system. With the help of a Finite element analysis FEM (is often available as an additional module for the respective CAD system) the bodies can also be subjected to forces and examined for deformation and breakage.

Surface models are mainly used in design. Here the shape of the surface is most important and less the body itself. The surface model has no mass and no volume. It consists only of geometric surfaces, which, however, mostly do not resemble any known surface equations.

There are various options for creating such a model. For example, with Boolean operators such as merging or subtracting, models can be built from individual bodies (cuboids, cylinders, cones, etc.).

Another possibility is that Extrusion or rotation of a profile. During extrusion, a body with the corresponding depth or height is generated from a closed profile. The rotation also copes with an open profile and axis of rotation.

Most 3D CAD systems were developed for the Windows operating system. However, there are also some systems for Mac OS - the best freeware programs can be found here: CAD freeware for Mac operating systems.

General data formats

  • DXF (Drawing Interchange File Format)
    • is supported as an industry standard by all CAD systems
    • Problems when transferring some CAD formats (dimensions, font, etc.) - there is a possibility that the target system does not recognize them and information is lost
  • DWF (Design web format)
    • was designed by Autodesk and could be displayed in a browser using plugins
    • is no longer used
  • IGES (Initial Graphics Exchange Specification)
    • similar to DXF, but not that common
    • for 2D drawings and 3D models (surfaces)
  • STEP (Standard for the Exchange of Product model data)
    • is not supported by all CAD systems
    • In addition to geometry data, material properties, color, views, etc. can also be transmitted
    • ideal for use between different application areas such as CAD, CAM, CAE, PDM
  • STL (Initial Graphics Exchange Specification)
    • is mainly used to provide three-dimensional models in 3D printing processes
    • Models are made up of triangular areas

CAD applications - mechanical engineering

  • Autodesk® Fusion 360
  • AutoCAD (Autodesk)
  • CATIA (Dassault Systèmes)
  • Creo Elements / Pro (PTC - Parametric Technology Corporation)
  • Inventor (Autodesk)
  • SolidWorks (Dassault Systèmes)
  • Solid Edge (Siemens PLM Software)
  • NX (Siemens PLM software)

CAD apps for mobile devices

Flexibility and mobility are properties that are increasingly required by designers. With the help of mobile apps for smartphones or tablet PCs, technical drawings as well as 3D models can be opened, viewed and even edited.

The following lists are intended to help you choose the right CAD app: