What Is Computer Aided Drafting?
Drawing is considered to be a universal language which is understood by most of people as compared to same piece of information running into pages of text.
Drafting in similar lines is a technical drawing generally used by designers to graphically present ideas and represent objects necessary for a designed environment. A set of these drafted illustrations are composed of construction document.
The technical sketch, mechanical drafting and computer-aided drafting all fall under the umbrella of drafting. When we use computers to prepare the drafting documents, they are specifically referred as computer-aided drafting (CAD). CAD is the speed of revisions to a document, it allows for redrafting sections instead of entire drawing. It also allows for easy sharing of information.
The papers and films have been used in olden days for drawing and drafting as the drafting media. Sketching which forms one of the forms of drawing can be done on any size of the paper but all the technical drafting need to be done on specific standard sizes and type of papers.
The two main type of paper that has been traditionally used are the tracing paper and drafting vellum as the drafting media.
Tracing paper aka TRACE is a medium-grade white or slightly yellow tinted transparent paper that takes pencil / ink / marker well. Trace is generally used for preliminary draft and for quality check and redrafting for final version.
DRAFTING VELLUM aka TRACING VELLUM is a high grade white or slightly tinted transparent paper that makes more impressive final drafts. These were also used for reproduction.
Drafting Sheet Sizes
Drafting media are available in three major styles: rolls, plain sheets and reprinted sheets with borders and title blocks. According to ANSI (American National Standards Institute) in the United States an 8.5 x 11 inch piece of paper is an “A” size sheet. This is typically referred as letter size. The 11” X 17” are referred to as “B” size sheet of paper. The “C” size sheets are 18” x 24” and “D” size sheets are 24” x 36”.
The line weight is the light or darkness and width of line used for drafting. Manual pencil drafting, ink drafting and CAD drafting documents must encompass variety of line weights to demonstrate the drafting. The actual width of each line type area always relative to the size and scale of the drawing. For example in ¼” scale say like floor plan usually need smaller pen widths than a drawing in 1- ½” scale.
Leader lines are used to connect notes or references to objects or lines in a drafting. Leaser lines starts as a solid line and end in an arrow. Leader line may be drawn perpendicular, straight or at an angle as shown on the drafting aside.
The dimension line is used to show the measurement of an object. It is the prime source for showcasing the length, width and diameter drafted based on the system used for drafting viz-a-viz imperial or metric systems.
The title block and border shown below may vary based on drafting to drafting and organization requirement from one to another. These are very specific with respect to the type of drafting and organization for which these are drafted for. Having said that below is an illustration of a title block with border, the title block typically include the following items: name of the design firm doing the job – this could be in a larger, bolder text and include a logo if possible with address, telephone, web address, e-mail etc; Space for professional stamp or seal – depending upon type and scope of the project this is required; Revisions; Project or job number, date; Sheet Title – this page title is usually short and specifically states the drawing (s) on that page; Sheet number. Survey Field Books – Bound standard engineer’s field book for transit and level, 7-¼” by 4- ¾”