What is Architectural Drafting?

Architectural drafting converts vision and ideas into technical drawings and detailed plans for the construction of buildings, such as institutional, residential, and commercial buildings. It helps engineers and architects to outline the working data and details, such as structure type, codes, elements, and kind of materials.

Difference Between Drafter and Architect

Architects work on concepts and the development of a design that includes the end-use and final look of a building and incorporates features such as cooling, ventilation, heating, and sanitation systems. They also provide cost and site analysis on the basis of environmental studies.

Drafters work under architects or engineers to transform ideas into design and plans by using computer-aided design and drafting software, such as Autodesk AutoCAD, building information modeling (BIM), and so on.

Architectural drafters' employment is dependent on the needs of local industry and cyclical fluctuations in the economy, where the demand for qualified drafters can remain constant for the people who have prerequisite experience. Architectural drafting is a kind of learning the alphabet in the architecture field in which drafting is used for interior drawings.

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Difference between Drawing and Drafting

• Drawing or sketching is done freehand without utilizing scale and measurement.
• Drafting is a drawing when done with proper scale and measurement.

Types of Drafting

1. Technical drafting: used to transform ideas into drawing at an initial stage. Figure 1 illustrates technical drafting.

2. Mechanical drafting: This is the refined drawing done after a conceptual phase by using a scale, compass, triangles, French curves, and the likes. It also includes elevation, plan, sections, and other drawings needed to start the construction project.

3. CAD drafting: is done on a computer that can be revised easily.  It can also be opened in multiple windows for easy comparison and modifications. Figure 2 illustrates CAD drafting.

Standard Views Used in Architecture

Floor Plan 

Floor plans are fundamental to interior design. A floor plan is a bird's-eye-view diagram of the interior of a building, similar to a map. It shows rooms, doors, windows, door openings, and so on for a particular level of a building.

Site Plan 

A site plan shows site elements around the structure. It is very useful for the development of urban areas.

Elevation

This plan shows the exterior of the structure. It is a horizontal orthographic projection of the structure on a vertical plane.

Cross-section

This plan shows the section when the vertical plane cuts the object. It is a horizontal orthographic projection on a vertical plane, with the vertical plane cutting through the structure.

Construction Methods of Projection

The word projection means to extend an to the outer wall of the structure. There are several types of projection in architectural drafting:

Pictorial Projection

When the description of an object is understood in a single view, it is known as pictorial projection. It gives an idea about the shape but not the true size.

• Axonometric projection: This one view shows all three dimensions of the object when drawn on a plane of projection. All three mutually perpendicular edges remain inclined to the plane of projection.
• Oblique projection: Projectors are not mutually perpendicular to each other; only the front face of the object is placed parallel to the plane of projection.
• Perspective projection: All the projecting lines converge at a point.

Orthographic Projection

In this projection method, the object is represented in two or three views on mutually perpendicular projection planes.

Isometric Projection/Isometric Drawings

An isometric projection is a pictorial projection in which dimensions can be measured from the projection. In technical and engineering drawings, with this method, one can represent three-dimensional objects in two dimensions.

Drafting Sheet Size

As per the American National Standards Institute (ANSI), 8.5” x 11” paper is architectural; it is a print-friendly size. The B size sheet is 11” x 17”, the C size sheet is 18” x 24”, and the D size sheet is 24” x 36”.

Line Weight

The line weight is the increased or decreased width of the drawn line. There are additional guidelines and boundary lines, in addition to lines that are used to show a drawing. Guidelines are used to lay up the page, and borderlines frame of a page. Solid, uniformly wide, and dark pencil lines should run on the length of a page. If a line in a drawing needs to be modified, make sure to delete it completely before redrawing it in the right line weight and quality.

Line weight is important for a set of design drawings. Keep in mind that design drawings can be distributed to a variety of people, including the client, other designers or architects, manufacturers, contractors, and so on. Design drawings must have crisp and dark lines so they can be easily reproduced and clear copies can be prepared from them.

Lines and Line Quality

Guidelines or Construction Lines

4H - 6H pencil lead in a 0.3 mm pencil

At the start of a drawing, the construction or guidelines are drawn. These are temporary and used to create initial shapes. The weight of the line is very light, which means it should have a small width.

Bold Lines

B - 2B pencil lead in a 0.5mm or 0.7mm pencil

Bold lines are drawn with a wide width to indicate walls in a plan or outline perimeter in elevation.

Medium Lines

HB pencil lead in a 0.5mm pencil

These lines are drawn to give information inside an object and to draw doors, furniture, and so on.

Light Lines

H-2H pencil lead in a 0.3mm or 0.5mm

Light lines should be used to draw action lines, information lines, and pattern fill. The potential movement of an object is depicted by action lines. Information lines are drawn for information regarding dimension lines, centerlines, sections line, and so on. Fill patterns are the symbols that show the kind of material used.

Border Lines

2B- 4B pencil lead in a 0.7mm / 0.9mm pencil

These lines are drawn to create a margin on the drawing sheet and around the title block.

Line Types

Solid Lines 

These lines indicate visible objects that can be seen in the plan, as well as elevation.

Dashed Lines

These lines indicate hidden objects.

Break Line    

This line indicates that the extent of the drawing cannot fit on the size of the paper.

Center Line 

This line indicates the center of a plan, object, symmetrical object, and so on.

Section Line

This line indicates a cutaway view of the plan.

Dimension Line   

The measurement and dimensions of an object are indicated by this line. Writing dimensions, titles, labels, and other particulars on a drawing sheet is known as lettering. 

Context and Applications

The concept holds relevance in various undergraduate courses. It is mainly inculcated in degrees such as:

• Bachelors in Technology (Civil engineering)
• Masters in Technology (Civil engineering)
• Masters in Architecture
• Bachelors in Architecture

Practice Problems

1. In orthographic projection, what is the XY line referred to?

1. Reference line
2. Vertical line
3. Horizontal line
4. All of the above

Answer: a

Explanation: Reference lines as reference planes are horizontal and vertical planes, which are also principal planes.

2. In which of the following planes does the top view of an object project?

1. Vertical plane
2. Horizontal plane
3. Auxiliary plane
4. None of the above

Answer: b

Explanation: The horizontal plane as a projection of an object can be seen from the horizontal axis only.

3. What are the minimum number of orthographic views required to show all dimensions of an object?

1. 1
2. 2
3. 3
4. 4

Answer: b

Explanation: In an orthographic projection, the object is represented in two or three views on mutually perpendicular projection planes.

4. What is the ratio of the length of the drawing of an object to the actual length of the object called?

1. Shrinkage ratio
2. Representative fraction
3. All of the above
4. None of the above

Answer: b

Explanation: Representative fraction because the shrinkage ratio is the ratio of shrinkage length to the original length of the object.

5. What is the formula for the length of scale?

1. Representative fraction x minimum length required to be measured
2. Representative fraction x maximum length required to be measured
3. All of the above
4. None of the above

Answer: b

Explanation: The formula for length of scale is representative fraction x maximum length required to be measured. It is not possible to draw as long a scale as to measure the longest length in the drawing.

Related Concepts

• Projections
• Difference between drafting and architecture
• Line type and quality