COMPUTER AIDED DESIGN (CAD)

Computer aided design (CAD) uses an appropriately designed  software as a design tool to create, modify, analyze, evaluate, and optimize two  and three dimensional digital models with geometric boundaries prior to prototype development or project construction.

The key features of a computer aided design (CAD) system are as follows; geometric creation and modification, 2D and 3D modeling, parametric and non-parametric design, dimensioning and tolerancing, material properties and rendering, simulation and analysis and collaboration and data exchange.

Geometric creation and modification are the fundamental building blocks of CAD design. The array of tools required to do this are obtained from the draw tool box and are used in conjunction with other tools to create geometric shapes such as points, lines, curves and surfaces to form complex designs.

2D and 3D modeling which is the main goal of CAD designs used to create, modify and edit models using tools from the modeling tool box. This operation may invoke commands such as extrude, sweep, loft, revolve etc.

Parametric and non-parametric designs are two different approaches to CAD design. While parametric design is focused on using parameters such as dimensions, angles, and constraint to define the shape and behavior of the object, non-parametric design focuses on creating design without using parameters, instead using geometric shapes and curves to define the shape of the object.

Dimensioning and tolerancing are critical component of CAD design; its use ensures that the resulting designs are accurate and manufacturable.

Material properties assigns  materials property to a model such as density, elasticity, thermal conductivity etc. while rendering generates photorealistic images of the design object or model using various rendering techniques such as ray tracing, global illumination  etc. Subsequently  texture and appearance may also be added  to the design object or model to enhance its visualization and realism.

Simulation and analysis enables designers to test and optimize designs, this may involve structural analysis, thermal analysis, fluid dynamics, dynamic simulation etc.

Structural analysis analyzes structural behavior of designs including stress, strain and deformation.

Thermal analysis analyzes the thermal behavior of designs including heat transfer and temperature distribution.

Fluid dynamics analyzes the fluid dynamics behavior of designs including fluid flow and pressure drop.

Dynamic simulation analyzes and simulates the dynamic behavior of designs including motion and vibration.

Collaboration and data exchange  tool box uses tools to enable designers to work together and share data using data exchange formats such as STEP(standard for exchange of productivity), IGES (initial graphics exchange specification), STL (stereo lithography), OBJ (object file format), VRML (virtual reality modeling language) etc.

A CAD system comprises of a hardware and software components. Thus for effectiveness the hardware component must closely match the software requirements. Generally for most CAD systems , the hardware requirements are; a fast processor (with multiple cores, at least 4 to 6 cores), a RAM  memory of at least 16GB or more, a graphics card or graphic processing unit (GPU) with a high performance graphics capability such as NVIDIA GeForce or AMD Radeon pro or a graphics card of at least 4GB VRAM, fast and large capacity storage such as solid state drive (SSD) to store CAD  and system files, a display monitor of high resolution of at least 4K with high dynamic range (HDR) capabilities, input devices  such as 3D mice, keyboard, tablets etc. that enables users to interact with the CAD software,. Output devices such a; printers, plotter, 3d printers etc., are used to print CAD designs.

The software used in CAD systems consist of the CAD software, operating system software and drivers and utilities.

The CAD soft wares are multiproduct from different manufacturers or vendors with different capabilities. The main CAD software used today are Autodesk AutoCAD, solid works, fusion 360, sketch up  and many others too numerous to mention. The CAD software enables users to create, modify and analyze digital models.

A 64 bit operating system such as Windows OS, Linux OS or Mac OS is adequate to support the most exacting CAD software.

Drivers and utilities are necessary software components that facilitate communication between the CAD software and the installed hardware components.

The engines governing all CAD software are the number of tool boxes they offer. Tool boxes are collection of software tools and features that enables users to create, modify and analyze 2D and 3D designs and they are as follows; drawing, 3D modeling, assembly and constraints, simulation and analysis, rendering and visualization, documentation and drafting, collaboration and data management, manufacturing and  CAM, reverse engineering and scan, electrical and electronic design, civil and architectural design, mechanical and machine design, product design and engineering tool box. However this list is not exhaustive.

The advantages of CAD system is as follows; the use of CAD system results in improved accuracy with minimum errors, its use improve the efficiency of the CAD design  process. It use enables real time collaboration across many countries. It use results in reduced project time and cost. It use enables designers to visualize and analyze designs prior to prototype development or project construction.

However its main disadvantages are; the steep learning curve required to use CAD systems as well as the high initial cost, the dependence on technology, limited creativity and compatibility issues, data loss and data exchange issues with different CAD systems are the main drawbacks.

CAD systems find widespread application in the following industries; architecture, engineering, product design, aerospace and automotive industries.

 

The future of CAD is based on the trends and development in the following technologies;  Artificial intelligence (A.I) powered CAD software will enable designers to create more complex and optimized designs. A cloud based CAD software will enable real time collaboration and access to designs from anywhere in the world. Virtual and augmented reality (VR/AR) technologies will enable designers to immerse themselves in designs and interact with each other during the life time of the project. Generative artificial intelligence (A.I) will enable or generate design option on the fly or based on specific constraints and parameters. CAD software will be developed with sustainability in mind, enabling designers to create more environmental friendly designs.

SOURCES;

• CAD/CAM principles and applications by Ibrahim Zeid.
• Computer aided design (CAD) : A practical approach by David A. Madson and David P. Madson.
• CAD/CAM: computer aided design and manufacturing by S.S Rao.
• The CAD guide book by Stephen J. Chapman.
• CAD: principles and applications by Richard H. Crawford.