2D CAD Modeling
Two dimensional (2D) CAD (computer-aided-design) models enabled drawing quality improvements in product design and engineering over manual drafting. Prior to the advent of economical desktop computers skilled draftsmen spent hours laboring with graphite lead pencils on velum and Mylar to achieve engineering quality documentation for fabrication and production manufacturing. The process required tedious checking to eliminate errors wherein modification required erasures and redrawing over and over on the same sheet. Large projects had many drawing documents linked to one another that required procedural revisions and archiving.
Two dimensional (2D) CAD (computer-aided-design) was a great step forward in moving from the drafting table to the desktop computer. The graphical display capabilities of the desktop computer enabled a user to graphically draft using mouse, keyboard strokes, text line commands, and tablet with stylus. Each CAD system had its own (UI) User Interface. While manual drafting may have actually been faster in the early years, two dimensional (2D) CAD (computer-aided-design) technologies allowed endless changes to be made with sharp clean printed copies printed without limitation. It was easy to export the CAD drawings in PDF format for viewing and printing on any non-licensed computer.
Two dimensional CAD is still used today for products that have simple orthographically defined geometry. It is useful especially for PCB layout and design wherein the modules being created are essentially a composite layering of 2D geometry. Parts that can be machined out of stock material are easily programmed for two dimensional cutter paths using 2D CAD drawings.
Two dimensional CAD is often used to make quick layout studies and linework for graphic design. Most CAD system can import DXF (Autocad drawing exchange format) and DWG (Autocad native file format). Some CAD systems such as SDRC (Structural Dynamics Research Corporation) can import a native Autocad 2D file and use its geometry to create solid extrusions or revolved forms.
Parametric dimensioning has been implemented in 2D CAD such as AnvilCad Lite which boasts the world's most powerful parametric kernel. Parametric dimensioning is akin to spreadsheets for financial tools. In a spreadsheet, if a number is one cell is changed, all cells that reference that cell automatically update to reflect the revised calculations. In CAD modeling, parametrics work in a similar way. Consider a rectangle with dimensions for length, width. If the dimension for the width is modified, the rectangle will automatically change its size to reflect the new dimension. Parametrics add a level of complexity to CAD modeling that allows the modeler to create "intelligent models" that respond to changes in a predictable and automated way. Parametrics take CAD modeling to a new level wherein a true professional modeler can skillfully capture design intent with a flexible model for efficient modification and part iterations. AnvilCad Lite 2D features all generic operations involving curves intersects, offsets, trims, extends, dimensions, labels, and boundaries and can use points, lines, circles, conics and splines. It also features section and curve analysis tools to evaluate curve continuity.
Porcupine is a typical curve analysis tool. It utilizes isolines which are line normal to the curve a regular intervals. The length of the isolines is proportionate to value for the curvature at that point on the curve. The ends of the isolines are connected by a derivative spline that graphically represents the changing curvature of the spline.
In summary, 2D CAD tools continue to be useful for designers and engineers in bring products to market. While 3D CAD tools offer far more powerful solid modeling functionality, not all industries require 3D data and the simplicity of 2D CAD makes it easy to apply.