Definition of Technical Drawing

   YourDictionary defines a technical drawing as a drawing or plan, rendered to scale, used to communicate direction and specifics to a group of people creating something. Engineers, contractors, plumbers, electricians, landscape architects, inventors and others use technical drawings to create a master plan or blueprint. The blueprint or plan communicates the necessary details among the workers to build the object detailed in the plan
 
Drafters are men and women trained in the art of technical drawing. Another term for a person skilled in creating technical drawings is a draftsman, although modern practitioners prefer the term drafter. Among electrical and mechanical engineers, the person on the team responsible for creating the technical drawing may also be referred to as the designer.

What Do Technical Drawing Look Like?

Technical drawings contain geometric figures and symbols to convey the scope and details of the project. Many professions, such as plumbing, use their own suite of unique symbols. Right angles, parallel lines, curves and symbols constitute the technical drawing. To those on the team, each line or symbol conveys a specific about the project.
It is imperative that technical drawings be accurate. If the drawing is off by even centimeters, the actual work may be off quite a bit too. This leads to disastrous consequences and costly delays in construction.

Tools for Technical Drawing

Technical drawings existed throughout time. Archaeological evidence included in a recent issue of Smithsonian magazine suggests that the architect of the Greek Parthenon scratched a technical drawing onto the marble floor to guide his workers! From ancient times to the present day, most drafters used a drafting table or a special table with slanted top and parallel rulers on either side. The parallel rulers on the sides of the table slide across the surface to hold the paper in place. Other tools include the T-square and compass.
A special device called the pantograph helped usher in the modern use of mechanical and computer-assisted design (CAD) While some drafters continue to use the drafting table and handheld tools, CAD helps drafters output technical drawings accurately and efficiently.

Tips and Tricks - Converting paper drawings

This article describes a process that produces computer-generated isometric guides directly from a scan of an engineering drawing. The following is a step-by-step description that will produce a product illustration directly on the computer from paper engineering drawings. Compared to traditional methods, it reduces the cost of an illustration by approximately twenty-five percent and can provide a further cost advantage due to the extraordinary increase in throughput. Our volume has more than doubled since we implemented this process.

Step 1: Scanning
Scan the engineering drawing using a resolution suitable to its size and complexity. Scan into three pieces, "Front," "Side," and "Top." After scanning the engineering drawing, erase extraneous items such as call outs, title blocks, dimensions, etc.

Step 2: Auto-Trace
Auto-trace programs, which convert scanned raster images to vector graphic files, need their settings modified to produce acceptable results. To do this, open Corel Trace, select the batch tool, select your scans, select Trace - Edit Options -choose the Lines Tab and use the following settings:

* Curve precision - Very Good
* Line Precision - Very Good
* Target Curve Length - Medium
* Sample Rate - Fine
* Minimum Object Size - 5 pixels
* Outline Filter - None
* Max Line Width - 16 pixels
* Create lines of uniform width - 1 pixel
* Check - Horizontal and Vertical line recognition
* Check your File - Save Options - Save Options Directory - Change the Default Directory to the directory where you want the vector graphic (*.eps) files saved.
* Now launch the Auto-trace function by clicking on - Trace All
* Close the program when Corel Trace is finished.

Step 3: Create a Master Isometric Ellipse
To create a master ellipse, open CorelDRAW to a new drawing, select the ellipse tool (circle in the Toolbox) and while holding down the Control Key create a perfect circle. Then use the transform tool to apply a vertical scale of 57.4 percent. Using the Transform Roll-up, rotate the ellipse 120 degrees and Apply to Duplicate twice. You will now have a "top," "front," and "side" ellipse. Save the result as Ellipse.cdr and keep that as a master. Select all three ellipses and copy them to the clipboard.

Step 4: Create Layers
Start a new drawing and paste the ellipses you just created onto the drawing. Reduce them to 25% of their original size and place them outside the paper border. In order to differentiate between the auto traces when they are imported into CorelDraw, they need to be color-coded. Open the Layers Roll-up and create the following three new layers with the stated names and settings:

* Front - Select Visible, Deselect Printable, Deselect Locked, Select Color Override and choose Red.
* Side - Select Visible, Deselect Printable, Deselect Locked, Select Color Override and choose Blue.
* Top - Select Visible, Deselect Printable, Deselect Locked, Select Color Override and choose Green.

Printable was deselected so that when Print Preview is invoked the Auto Traces will be invisible. Locked was deselected so that the auto traces can be moved.

Step 5: Import
Import the Auto-Traces onto their respective layers correcting any orientation and rotation as necessary. Save the drawing.

Step 6: Create the Front
From the Layers Roll-up, deselect MultiLayer and select the "Front" layer. Select the trace and from the Transform Roll-up, choose a 86.6 horizontal scale and apply, then a -30.0 degree vertical skew and apply. The result will be the guide for the left face of the illustration.

Step 7: Create the Side
From the Layers Roll-up, select the "Side" layer. Select the trace and from the Transform Roll-up, choose a 86.6 horizontal scale and apply, then a 30.0 degree vertical skew and apply. The right side guide is now complete.

Step 8: Create the Top
From the Layers Roll-up, select the "Top" layer. Select the trace and from the Transform Roll-up, perform a vertical scale of 86.6% to your trace and apply. Choose a -30.0 degree horizontal skew and apply, then choose rotate -30.0 degrees and apply. You now have a "plan view" guide in isometric. Next, choose each layer and position them so that everything lines up at the front, right, top corner.

Step 9: Setting Preferences
In order to control how the software produces vector objects, some of CorelDRAW’s default settings need to be changed. Choose Preferences (Ctrl + J) and set the following:

* Place Duplicates and Clones - Horizontal = 0.000, Vertical = 0.000. These settings will ensure that duplicated objects are not offset.
* Nudge = 0.010. The default nudge is too large for technical work. Using this setting gives you more control of your work. A thin sheet metal thickness can be shown with two or three nudges.
* Constrain angle = 15.0 degrees. This is the Corel default and is perfect for an isometric projection.
* Miter limit = 45.0 degrees. This is the Corel default.
* Undo levels = 4. Limiting undo levels will conserve system resources.

Step 10: Constraining lines on an isometric axis
Make Layer 1 active. Choose your pencil tool (straight line) and while holding down the control key on the keyboard draw a line. While still holding down the key, watch the status line while moving the end point in a good sized circle you will note that the line jumps in 15 degree increments. Since the normal axis in isometric is 30 degrees, this will provide all "On Axis" and most of the "Off Axis" conditions you will encounter. Releasing the control key permits drawing on any angle.

Now the magic can happen. If you combine the ellipses, constrain the angles, and use the Auto-Traces you have everything you need to complete an illustration. I usually require approximately ten minutes to complete the above and begin drawing. In this time conventional methods would be less than twenty percent complete.

In a time of restricted budgets and impossible deadlines a process like this can be an invaluable tool. Our per-person output is a multiple of the organizations we compete with who use "high tech" methods to produce their isometrics. In the technical illustrating field this may be as close to "good, fast, and cheap" as we are likely to get.

GLOBAL STANDART

1 SCOPE:
This standard establishes uniform drafting practices for preparation of engineering drawings.
2 APPLICATION:
This standard applies to all new Sauer-Danfoss (SD) Engineering drawings.
3 GENERAL:
To ensure that drawings are unambiguous, international standards (ISO and IEC) are used for general principles of presentation, definitions, scales, dimensioning, symbols, tolerances, thread designations etc.
If no international standards are available, European standards (EN), national standards or Sauer-Danfoss Standards and Guidelines are used.
The reference to GS-0074 is as shown in figure 1.
If there is a reference to GS-0074, one or more of the Sauer-Danfoss documents listed in this Guideline are used.
If other standards are used, they must be the subject of special reference.
If a drawing refers to a standard that conflicts with a standard in the body of GS-0074, then the standard noted on the drawing shall have priority.
The English language version is the original and the reference in case of dispute.

Technical drawing

If its technology don't fear CAD Drawing India is near

When it comes to technicalities or operations, management guys show the white flag. The moment someone utters in the organization “Let us move into some technology jargons say 2D, 3D, vectors or similar stuff, its the top management which raises its hands in tremor. CAD short of computer aided design is one such scary technical monster which as usual turns the highly trained and qualified professionals in the organisation, apprehensive. But anyway that monster has been taken care of by CAD Drawing India. Here stands the company as a pillar guarding the diverse industrial sector from technological pitfalls. Good news for the construction and manufacturing industries, “No more drafting of technical and engineering drawings of products and buildings manually”. CAD Drawing India with its CAD Drawing Services has elevated the whole platform of engineering and technical drawings of product designs, building layouts and blueprints etc. to a new era of augmentation. Now strictly taking a step to purely mechanical details, CAD Drawing Services is used to generate design and documentation through computer technology. The CAD environments of CAD Drawing India aids the construction and manufacturing giants in aligning the design processes, drafting documentation and manufacturing processes. Its this technological potential gifted by CAD Drawing India which has empowered the construction companies to design curves and figures of their building layouts in two dimensional space, or curves, surfaces and solids in three dimensional objects. Carrying the presence of firms into a raised pedestal or epoch of advancement, CAD Drawing India has spread its ambit into a list of industries including automotive, ship building, aerospace, architecture, prosthetics etc. The list does not end here. CAD Drawing Services has managed to penetrate into a fissure of the entertainment industry. These services are also used to generate computer animations for special effects in movies and advertising. One profitable ramification of the of the ingression of CAD Drawing India is that there would be a reduction in the salary costs of the construction firms as there is no more requisite for hiring drafts-men for any manual work. No intricacies, no hyperbolic comments, no irony. Lets just keep it simple “ Why to fear, if CAD is near”. CAD Drawing India is benignly trying to offer its technology rich services to organisations with an intention to share the anguish produced from the cumbersome load of work faced by organisations. They understand the work culture complexities prevailing in the organisations. Their message is straightforward and clear, “If you have to many functions, outsource some loads to us”.

Engineering drawing McGraw-Hill Science & Technology Encyclopedia

A graphical language used by engineers and other technical personnel associated with the engineering profession. The purpose of engineering drawing is to convey graphically the ideas and information necessary for the construction or analysis of machines, structures, or systems. See also Computer graphics; Drafting; Graphic methods; Schematic drawing.

The basis for much engineering drawing is orthographic representation (projection). Objects are depicted by front, top, side, auxiliary, or oblique views, or combinations of these. The complexity of an object determines the number of views shown. At times, pictorial views are shown. See also Descriptive geometry; Pictorial drawing.

Engineering drawings often include such features as various types of lines, dimensions, lettered notes, sectional views, and symbols. They may be in the form of carefully planned and checked mechanical drawings, or they may be freehand sketches. Usually a sketch precedes the mechanical drawing.

Many objects have complicated interior details which cannot be clearly shown by means of front, top, side, or pictorial views. Section views enable the engineer or detailer to show the interior detail in such cases. Features of section drawings are cutting-plane symbols, which show where imaginary cutting planes are passed to produce the sections, and section-lining (sometimes called cross-hatching), which appears in the section view on all portions that have been in contact with the cutting plane.

In addition to describing the shape of objects, many drawings must show dimensions, so that workers can build the structure or fabricate parts that will fit together. This is accomplished by placing the required values (measurements) along dimension lines (usually outside the outlines of the object) and by giving additional information in the form of notes which are referenced to the parts in question by angled lines called leaders.

Layout drawings of different types are used in different manufacturing fields for various purposes. One is the plant layout drawing, in which the outline of the building, work areas, aisles, and individual items of equipment are all drawn to scale. Another type of layout, or preliminary assembly, drawing is the design layout, which establishes the position and clearance of parts of an assembly.

A set of working drawings usually includes detail drawings of all parts and an assembly drawing of the complete unit. Assembly drawings vary somewhat in character according to their use, as design assemblies or layouts; working drawing assemblies; general assemblies; installation assemblies; and check assemblies.

Schematic or diagrammatic drawings make use of standard symbols which indicate the direction of flow. In piping and electrical schematic diagrams, symbols are used. The fixtures or components are not labeled in most schematics because the readers usually know what the symbols represent. See also Schematic drawing; Wiring diagram.

Structural drawings include design and working drawings for structures such as building, bridges, dams, tanks, and highways. Such drawings form the basis of legal contracts. Structural drawings embody the same principles as do other engineering drawings, but use terminology and dimensioning techiques different from thoses shown in previous illustrations. See also Nomograph.
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Engineering drawing

Overview
Technical drawing of a certification listing for a firestop system

Engineering drawings are usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance (such as typefaces and line styles), size, etc. One such standardized convention is called GD&T.

Each field in the Fields of engineering will have its own set of requirements for the producing drawings in terms line weight, symbols, and technical jargon. Some fields of engineering have no GD&T requirements.

The purpose of such a drawing is to accurately and unambiguously capture all the geometric features of a product or a component. The end goal of an engineering drawing is to convey all the required information that will allow a manufacturer to produce that component.

Engineering drawings used to be created by hand using tools such as pencils, ink, straightedges, T-squares, French curves, triangles, rulers, scales, and erasers. Today they are usually done electronically with computer-aided design (CAD).

The drawings are still often referred to as "blueprints" or "bluelines", although those terms are anachronistic from a literal perspective, since most copies of engineering drawings that were formerly made using a chemical-printing process that yielded graphics on blue-colored paper or, alternatively, of blue-lines on white paper, have been superseded by more modern reproduction processes that yield black or multicolour lines on white paper. The more generic term "print" is now in common usage in the U.S. to mean any paper copy of an engineering drawing.

The process of producing engineering drawings, and the skill of producing them, is often referred to as technical drawing or drafting, although technical drawings are also required for disciplines that would not ordinarily be thought of as parts of engineering.