Electrical Computer Aided Design – Automotive & Aerospace

Electrical Wire Harness design for Maserati Ghibli. Image courtesy of Siemens PLM Software.


In the modern engineering world Computer Aided Design aka. CAD is becoming the most important field. It not only helps a huge cost savings to the company but also gives a rapid product development capability. 

Multiple pioneer software industries have developed a variety of CAD tools around the world. Some of the notable ones include AutoCAD, NX, CATIA, Pro/ENGINEER etc.

In automotive and aerospace industries, CAD has been playing a major role for a couple of decades. Due to increasing complexity of electronic features as well regulatory requirements physical design and testing is becoming near to impossible without virtual design and simulation. That is where the CAD comes into play.


The general architecture of the electrical CAD and can be structured as follows

  • Device Component Design that includes equipment and devices. Example: Battery, Radio, Antenna etc.
  • Active Harness Component Design that includes electrical connectors, splices, ring terminals etc.
  • Passive Harness Component Design that includes fasteners, troughs, grommets, brackets etc.
  • Wiring Harness Design that includes the various wiring harnesses. Example: Seat Wiring, Transmission Wiring, Body Wiring etc.


Best Practices (Design)

For rapid development and reusability it is always best to have Product Data Management application in place which can further structured into

  • Device Component Design Template Management
  • Wiring Harness Design Template Management
  • Standard Component Library Management
  • Standard Operating Procedure Document Management

Templates are developed based on the best practices learned over the years in that area of design. It includes design checks, design standards, so that even a new user can adapt the design requirements without prior knowledge of the new design he/she is assigned to.

Along with design templates, SOP or Standard Operating Procedure document plays a vital role in Computer Aided Design. For example if a device is to be designed that  is going to be installed in a splash zone, SOP and Template will automatically guide the designer what are the design requirements.

Modular/End Item Assembly Design

Even though the final product may look depending on consumers requirement but many of the internal components/features are cross functional. Example: A RAM truck is totally different from a Pacifica van, however both may be using the same battery, gps antenna.So it is better to have a modular design approach rather than a bulk design approach. In the given example above, if each module (component) battery, antenna are designed and managed separately they can be reused over and over in multiple platforms. Similarly components of a specific functional group can be designed and managed as independent sub-assembly which later can be assembled to the required platform.        

Coordinate/Axis System Definition

One of the important aspects in CAD is the definition of the global and local coordinate/axis definition. A complete design could be assembly of many sub-assemblies and end item components. It is always important to have a standard definition of the global and local coordinate system defined so that these sub-assemblies and end items can be assembled in the virtual world very quickly and efficiently. 


All of the wheels on a vehicle or airplane are the same but they are located at different locations. So rather than designing the wheels for multiple times, a single wheel can be designed and positioned at multiple locations.

Standard coordinate/axis system definition also gives the design team to make a right decision whenever there is any design modification needed. Following two examples can give a little more idea of the above statement.

A driver door on a Left Hand Drive (LHD) vehicle needs to be mirrored for a Right Hand Drive (RHD) version of the same vehicle. A standard coordinate/axis system quickly helps the design team to verify if the door will fit or there needs to be modification required to fit the same driver door on the Right Hand Drive (RHD) version of the vehicle.   

Fig: Global Coordinate/Axis System

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