Elements of Computer Aided Design
- A computer-aided design is the generation, creation, development and analysis of a design or system using computer software.
- As technologies improve and software becomes more powerful, so do the opportunities for designers to create new and exciting products, services and systems.
- Greater freedom in customization and personalization of products has a significant impact on the end user.
- The ability to virtually prototype, visualize and share designs enhances the whole design cycle from data analysis through to final designs.
Types of Computer Aided Design
2D CAD
- 2D CAD is traditionally used to produce 2D views on a design.
- Together they can form a fully orthographic projection.
- The use of CAD can allow for precise lines and measurements.
Surface Models
- Surface models are photo-realistic images of a product, offering some machining data but no data about the interior of the product.
- Surface models are hollow on the inside and thus aren't useful for testing functionality.
Solid Models
- Solid models are clear representations of the final product.
- They provide a complete set of data for the product to be realized including internal dimensions and volume.
- They can be used in computer testing to determine material strength, cost, etc.
Data Model
- A data model explicitly determines the structure of data or structured data.
- Typical data models include databases and information systems.
- Developments in information and communication technology (ICT) make a data model important to applications that use and exchange data.
Virtual Prototyping
- Virtual prototyping involves the use of surface and solid modelling to develop photo-realistic interactive models.
- These can be considered as digital mock-ups.
Bottom-up vs Top-down CAD
Bottom-up
Innovation Context
- Designing parts of a product individually, then assembling them together later.
- A design starts with very concrete, technical parts and elements, which gradually form the larger design entity.
- Develops from concrete to a more conceptual level. (Example: Design of the construction of the Mars Rover; based on core instruments).
CAD Context
- The principle of combining individually designed elements to a larger group of components, without embedded interdependency in the design.
- This means every change to the concept requires a lot of recalculating and realigning individual objects.
- Quicker to set up, but requires more time when changes are made later in the process.
Top-down
Innovation Context
- A design starts with a concept, on a more abstract level.
- As design specifications become more and more clear and limitations are determined, the design gradually moves to more concrete and technically detailed parts.
- Develops from conceptual level to concrete design.
CAD Context
- Top-down refers to how individual elements are designed with correlating interdependencies, which allows the designer to easily process any complex changes in the design.
- More time investment needed in the set up stage, but time saving when alterations or versioning is applied to the model.
Types of Computer Aided Design
Digital Humans
- Digital humans are computer simulations of a variety of mechanical and biological aspects of the human body.
- They can be used to interact with a virtual prototype.
- Digital humans can be used to represent joint resistance, discomfort, reach envelopes and visual fields.
- They can be used, for example, to measure the impact of clothing on human performance.
Advantages
- Quicker product development (more design iterations in less time).
- High product quality that meets human requirements more accurately.
- More thorough analysis of product safety aspects.
- Improves worker safety and reduce compensation costs resulting from accidents.
- Machines and equipment can be positioned to optimize cycle time and avoid hazards.
- Ensures optimal productivity; ensuring all needed tasks can be performed (safely) by real humans.
- Enables people to be trained without the need for physical prototypes or actual equipment and so reduce the cost of training personnel.
Virtual Reality
- Virtual reality is the ability to simulate a real situation on the screen and interact with it in a near-natural way.
- There are already a lot of fun applications for it, like Google Street View, Earth and Expeditions, but there are tons of possibilities for other areas, such as training for operations (both surgical as military), disabled can attend concerts or distant family events, enhancing education, and so on.
Haptic Technology
- Haptic technology is a technology that interfaces the user via a sense of touch.
- Also known as force feedback technology, haptic technology works by using mechanical actuators to apply forces to the user.
- You might have experienced it while using various game controllers that incorporated the early versions of this technology, providing the user with ‘force feedback’.
- The fiction series ‘Black Mirror’ also showcased how haptic VR technology might be incorporated into the human body in the future, causing serious ethical issues.
- You could, however also imagine how this technology could have great benefits: far distance (tele-)operating, restoring senses, etc.
Finite Element Analysis
- Finite element analysis involves the calculation and simulation of unknown factors in products using CAD systems, for example, simulating stresses within a welded car part.
- It tests the performance of complex parts.
- It could be used during the virtual prototyping stages to test the self-cooling efficiency of solar panels.
Advantages and Disadvantages of CAD
Advantages and disadvantages of using CAD vary in product design, architecture and graphic design.
Computer aided design, such as animation or virtual reality can reduce tooling, labor, energy and material costs.
However, they also come with drawbacks that only physical or graphical modelling can provide.
Advantages
- Changes to ideas can be made quickly and easily.
- Communicate with client, manufacture more easily electronically transferred.
- Avoid costly mistakes.
- Reduce costs as extra prototypes are not needed.
- Saves time through efficient work practices.
- High accuracy.
Disadvantages
- Software/Hardware costs
- Special training needed
- Steep learning curve
Additional Terms
Animation
- The ability to link graphic screens/stills together in such a way as to simulate motion or a process.
Bottom-up Modelling
- A designer creates part geometry independent of the assembly or any other component.
- Although there are often some design criteria established before modelling the part, this information is not shared between models.
- Once all parts are completed, they are brought together for the first time in the assembly.
Computer Aided Design (CAD)
- The use of computers to aid the design process.
Data Modelling
- A model that determines the structure of data.
Digital Human
- Computer simulation of a variety of mechanical and biological aspects of the human body.
Finite Element Analysis (FEA)
- The calculation and simulation of unknown factors in products using CAD systems. For example, simulating the stresses within a welded car part.
Haptic Technology
- Haptic technology is an emerging technology that interfaces the user via the sense of touch.
Motion Capture
- The recording of human and animal movement by any means, for example, by video, magnetic or electro-mechanical devices.
Solid modelling
- Solid models are clear representations of the final part. They provide a complete set of data for the product to be realized.
Surface modelling
- A realistic picture of the final model, offering some machining data. Surface models contain no data about the interior of the part.
Top-down modelling
- “Top down” design is a product development process obtained through 3D, parametric and associative CAD systems.
- The main feature of this new method is that the design originates as a concept and gradually evolves into a complete product consisting of components and sub-assemblies.
Virtual prototyping
- Photorealistic CAD-based interactive models that use surface and solid modelling. They can be considered 'digital mock-ups‘.
Virtual reality (VR)
- The ability to simulate a real situation on the screen and interact with it in a near-natural way.