Computer-aided design and manufacturing

Draft

Definition

“Computer-aided design (CAD) is the use of computer technology for the design of objects, real or virtual. The design of geometric models for object shapes, in particular, is often called computer-aided geometric design (CAGD).” (Wikipedia, retrieved 16:43, 24 June 2009 (UTC)).

“Computer-aided manufacturing (CAM) is the use of computer-based software tools that assist engineers and machinists in manufacturing or prototyping product components. Its primary purpose is to create a faster production process and components with more precise dimensions and material consistency, which in some cases, uses only the required amount of raw material (thus minimizing waste), while simultaneously reducing energy consumption. CAM is a programming tool that makes it possible to manufacture physical models using computer-aided design (CAD) programs” Wikipedia, retrieved 16:43, 24 June 2009 (UTC).

CAD and CAM are kind of Electronic Design automation together with computer-aided engineering, etc.

See also:

• Fab labs (machines that build designs). The purpose of this entry is provide some background information about CAD/CAM formats and software that could be useful for building things in a (larger) educational context with fabbers (low cost 3D printers).
• RapMan, a cheap low-end 3D printer
• 3D modeling

File formats

See 3D file formats for a more systematic list of 3D modeling and CAD file formats.

3D Computer Modeling

Models can be built in various formats, such as RIB, DXF, 3DM, 3DMF, OBJ, X3D. For many fabbers, they then must be exported as .STL file,

The .STL format

The STL format is an interchange format for 3D models. It describes a raw unstructured triangulated surface of an object and is widely used for rapid prototyping and computer-aided manufacturing.

Scanners

Polygon File Format or the Stanford Triangle Format. (.PLY)

CAD standards

See CAD standards (Wikipedia).

Software

Input to low-end 3D printers

• RepRap (see Fab labs) uses g-code for CAM
• RapMan uses g-code files made from .STL (with skeinforge)
• Fab@Home works with any CAD program that can export to .STL

Free CAD software

• OpenScad is a software for creating solid 3D CAD objects. It is free software and available for Linux/UNIX, MS Windows and Apples OS X. Something like a 3D-compiler that reads in a script file that describes the object and renders the 3D model from this script file
• Open Cascade
• CoCreate Modeling Personal Edition
• FreeCAD is a general purpose 3D CAD modeler.
  • FreeCAD (Wikipedia)

Viewers

• SolidView light is a free program with support for SFX, STL, SolidWorks, VRML, and OBJ CAD files. I.e. it can be used to look at STL files.
• Pleasant3D Visualization of STL plus minor editing in order to be printable on MakerBots/Rapmans: Move, rotate, resize.

Cheap CAD software

• Alibre Design ($97 for the standard edition, free trial)

3D modelers (like Blender, Art of Illusion, etc.)

• See 3D modeling.

Links

General and links of links

• Computer-aided design (Wikipedia)
• Computer-aided manufacturing (Wikipedia)
• CAD standards (Wikipedia)
• 3D computer graphics software (Wikipedia)
• Comparison of 3D computer graphics software (Wikipedia)
• Electronic design automation (Wikipedia)
• Comparison of CAD editors for CAM
• computer numerical control (CNC), CNC Concepts, Inc., see e.g. the [http://www.cncci.com/resources/links.htm links section.
• Fab@Home Design Tools Page

Free multi-purpose modelling software

• Ayam,a free 3D modelling environment for the RenderMan interface.
• Blender, a free open source 3D content creation suite.
• Caligary, is a free 3D computer graphics and animation software.
• Art of Illusion is a free, open source 3D modelling and rendering studio.