A Section Drawing:

An orthographic projection for architectural design and communication

A section drawing is an orthographic projection. It is similar to a floor plan drawing, but it changes the cut plane from horizontal to vertical direction that is perpendicular to the horizontal line. A building section drawing helps to reveal internal spaces of the building.

A building section is one of the most helpful tools for architectural design discovery and examination. It allows a viewer to understand vertical spatial connection. At the initial stage of design, I often utilize section drawing as a medium to explore spatial possibilities of my architectural design. A building section depicts a connection between each element of architecture such as floors, walls, roofs, vertical openings. In addition, it offers insight into the quality, light, flow, and movement of spaces as well as the proportion of rooms and spaces in terms of width and height. Drawing a building section does not have to be a formal approach.

A simple method of drawing such as freehand section sketching can be a very useful technique to generate and reveal our mental images of architectural design.

Section drawing not only can help reveal the connection of interior spaces. It’s also utilized to examine the connection of a building to its site and surrounding area. In this case, it is called a site section.

Speculative Sketching

Drawing by Otto A. Chanyakorn

I see the benefits of using drawing or sketching in design process in two functions. first, I use drawing as a communication outlet. Besides verbal communication, drawings are one of the most important method of communication in architectural design that I normally use to convey my ideas.  A type of drawings that we produce after we have developed a clear ideas in our head. They need to be concise in order to convey  our imagination to the viewers. They also take a longer time to produce. Most of the time, I utilized computer aid software to produce this type of drawings.  Second, I always use drawing as a tool to visualize my imagination and conjure up my creativity. It is an open-ended type of sketching that could let us to a further discovery in our design journey or even for future references.

At the beginning the design process, we will not have a clear pictures what  we actually want in mind. Ideas will continue to flow to our mind constantly. The only method that allows me to capture them and keep up with my imagination  is sketching.  There is no definite types of drawings that I use to visualize my ideas. They could be diagrams, thumbnail sketches or anything that serves the purpose of capturing my thoughts. It is ways of thinking and working that formalized or clarifies  my ideas.

In Vinod Goel the author of “Sketches of Thought, he discovered that implementing freehand sketching as a primary tool for preliminary stages of design optimized exploration, and produced variation of design ideas. Freehand sketching enhances a high level of ambiguity, which optimizes design solutions. The intimate connection and processes of embodying a design task without an interruption from external tools are vital for the initial phase of the design process.

To develop the fluency in speculative sketching, one must practice on a regular basis until the circularity of mind and hand become unify. Practice is an answer. We will need to practice until drawing each line down on paper is a natural response to we are picturing  in our mind.

Axonometric versus Perspective

No drawing can capture reality entirely.  A drawing represents a particular perception of human experience. This rule applies to drawings in architectural communication as well. The question is when and how to justify the right type of drawing to accomplish the task at hand. This requires an understanding and evaluation of the function and the utilization of an appropriate drawing type in order to be successful.  This article will compare the function between axonometric and perspective drawings and their usages in architectural design process. 

Drawing by Sara Reh, Timothy Hefler & Brendon Bangert

In the Middle-Ages, axonometric drawing was used mainly for military purposes.  Due to its measurability and preciseness, it was the optimal medium of communication for building walls and other constructing facilities to protect their cities. Since errors meant the loss of life and their cities, precision was critical.  Axonometric drawing is parallel projection drawing that offers a unique view beyond our actual perception. Axonometric drawing, for Akos Moravanszky, has been considered an efficient method of visualizing spatial relation to true size. It is safe to say that we hardly see this type of view through the naked eye on a daily basis. In architectural practice, I normally utilize an axonometric drawing (an Isometric) to visualize constructional methods in design that relate in order to reveal the sequence of construction or material components.  It is an effective type of drawing that I often encourage students to use for exploring their constructional understanding in architectural design.  According to Akos Moravanszky, axonometric projection was considered an objective means of technical drawing. Akos cited that Auguste Choisy was be able to mediate structural clarity of major spatial construction in his studies. Due to the effectiveness of axonometric drawings, there have been many respected architects from historical eras to contemporary times that have utilized this type of drawing as an important vehicle in their design process. The drawing above is an example of an axonometric drawing by students in my steel building technology course. It was utilized to capture the constructional sequence and building components as part of their design exploration in addition to the conventional method of drawing (detail section drawing).


Drawing by Katherine Brewer

Unlike an axonometric drawing, a perspective drawing is often used to capture a particular angle of our perception as a being in space.  It is a useful type of drawing in design purposes to visualize and capture our perception in architectural spaces. Its function is similar to the photographing method.  It is used to represent our imagination. Well-known architect, Steven Holl, often uses perspective drawings along with other types of drawings to capture his architectural imagination in his water color sketches before the ideas are further examined. Perspective drawings are also widely used by architects to present their design ideas to clients since viewing this type of drawing requires little background knowledge to understand its content as well as its closeness to our actual perception when we conceive idea of spaces in three dimensions in contrast to axonometric drawings. In the Renaissance era, perspective drawing was widely used as the dominate medium due to its character.  The example above depicts the ability of a perspective drawing to capture our perception in viewing a space in three dimensions. 

When practicing architecture, it is critical to be able to evaluate which type of drawings shall be used  as a vehicle of design in order to explore the best possibility of design. Axonometric drawings seem to be an appropriate medium to explore and explain constructional methods in design while perspective drawings are good for three dimensional explorations in design as part of our human perception in architectural spaces. However, there is no distinct line of usage between the two. It is based on the experience and purpose of how and when to use them. The base line is understanding their capacities and functions which help to justify what type of drawing should be used to serve our purpose.

Drawing Method of Auguste Choisy

One of the common type of drawings that I normally use is Isometric drawing.  I often use this type of drawing to review three dimensional aspects of my design or constructional aspect of architecture. I also use Isometric drawing  when I design furniture for my wood working practice. The drawing offers a unique point of observation.  Most of my Isometric drawings will be visualized from the bird’s – eye view that allows the viewer to see the object from above. It is useful when utilizing this type of drawing to appropriate task in design precesses. Particularly for my object design (Wood furniture design) because it allows me to exhibit the entire elements of an object , and an Isometric also allowed me to implement scale directly into a drawing.

However when it comes to architectural design, I confronted the difficulty to visualize interior spaces  thorough bird’s -eye view isometric drawings because the view point is not related to regular level of human perception. I recently came across the book by Auguste Choisy called “ Historie de l’ architecture”.  Besides the content, the book depicted marvelous drawings in various types. One of those were Isometrics and cutaway drawings ,but instead of using bird’s -eye view technique, Choisy selected a worm’s – eye view to convey his point of architectural observations. Choisy’s drawings allow viewers to visualize quality of interior spaces over exterior of architecture. I personally think this drawing method is profoundly constructive in architectural design. Particularly when we need to examine quality of interior spaces of our design. Since qualities of interior spaces is an essence of creating architecture, utilizing Choisy’s method of drawing could be an answer. As far as I can recall, Rafael Moneo Architect used this method of drawing in his project, National Museum of Roman Art as well.

Figure-Ground Drawings

Drawing by Tomi Perl

Figure ground drawing is an important drawing typology as well as my favorite one, which I often use in my architecture and urban design processes. Figure ground drawing is an analytical drawing  that helps me to evaluate appropriateness when inserting a new design into an existing urban fabric.  In other words, figure ground drawings help clarify the order of existing urban morphology. It helps to justify the shape of new buildings in a certain level. Indeed it is a reduction drawing typology that is intended to eliminate and is fully focused on the relationship between open ground and buildings’ shapes.

When Colin Rowe submitted his proposal for a cultural competition “Roma interrotta” in 1978, he employed figure ground drawing as part of his drawing method for his proposal. Each of twelve renowned architects who participated in the competition were given a 1748 Nolli map as an important order of the existing urban fabric.  Rowe retained important elements of the city such as streets and plazas as existing conditions from the Nolli map.  Additional parts of his design proposal were created with various shapes that were filled in with black color to represent the shape of new buildings that ought to be new urban infill, which Rowe termed “ideal ground plans.”  It is a superimposed method of urban design. The result of his reinvention of using figure ground drawing as part of design strategy was remarkable. His proposal offered the opportunity of the city to capture the urban spatial quality and order of the existing urban fabric, but set free the new building design to be built in any era as long as they are aligned within existing urban order. For further understanding, please read “Urban Design Tactics” by Steven Peterson.

Typically in figure ground drawings, all buildings will be done in black Poche while leaving open land, streets, and plazas as white. I see figure ground as an another type of diagram drawing since it uses the reduction method of drawing.  I normally construct the drawing by using AutoCad, and I found that Cadmapper is a very useful website for this particular task.  The outline of each building will be drawn with thin lines (0.09 mm) and the buildings’ shape will be hatched with solid hatch. 1:2000 (Close to 1/160″=1′ in feet and inches) is an ideal scale for drawing figure ground in metric and it is likely the smallest scale that is being used in architectural drawing. The important elements that should be included with figure ground drawings are the north arrow and graphic scale.

The drawing above is an example of a figure ground drawing of Rome, Italy that was created by one of my students, Tomi Perl, in an urban design course as part of urban morphology studies. The drawing highlights the Pantheon in red the building of focus. With this approach, viewers will be able to spot the focused area of study easily.

Poche’ Technique in Architectural Drawings

Design & Drawing by Casey Revelle and Robert Konzelmann

In architecture, poche’ is the process of darkening the area of walls, columns, and other solid elements created by a cut plane . This process is frequently utilized in representing buildings and objects in plan, section, and figure-ground (drawings that create a high contrast between spatial areas and cut elements). Blackening the cut elements helps viewers easily identify the depth of elements in floor plans and sectional drawings.

Drawings represented in a smaller scale benefit from the high contrast nature of poche’; it is an ideal method for effective communication when drawings are intended to be displayed in a presentation-like format, or the audience is standing more than 3 feet (1 meter) away from the drawings. In contrast, if a drawing is depicted in a large-scale format, the poche’ method has the potential to dominate and wash out the main content of the drawing.

The main question then becomes what are the appropriate scales that the poche method can be used to enhance the outcome of plan and section drawings?

I frequently use poche’ when I need to display drawings in the initial phases of design that do not contain many details, but rather display the functional configurations in plans and spatial articulation in section drawings. Any drawings that utilize scales smaller than 1/4’=1’-0” or 1:50 benefit from this presentation method. Periodically, using a middle-gray value instead of black is appropriate for drawings depicted at a scale close to 1/4’=1’-0” to reduce the high contrast between cut elements and spatial void in plans and section drawings. By doing so, the elements represented do not visually dominate a composition and are less straining on the eye of the viewer.

Drawings that are depicted in a scale larger than 1/4’=1’-0” should use a hierarchy of line widths and weights to create depth of elements in the drawings.

The figure above illustrates how the poche technique defines the cut plane in the building section. The filled walls, floor plates, ceilings, and solid elements define the spatial aspects of the building and allow viewers to observe how the various building elements are unified, as well as establish a platform for other analytical studies to be incorporated such as solar studies as seen in the figure mentioned above.


Kidosaki House designed by Tadao Ando / Section drawing by Otto, A. Chanyakorn

Line type is one of the drawing elements that should be learned.  Each line type serves a purpose in drawing, and they also convey their own meaning in architectural drawings. Thus, in order to fully convey our communication in drawings, we should understand its functions.  I normally employ four line types in my drawings, and I personally enjoy the simplicity of utilizing only these four line types. Whether drawn on a computer or by hand, these line types help to convey  meanings in architectural graphic . Drawings are easier to read and interpret when line types are properly applied. The line types below are commonly used in my work:

Continuous lines use for cut and visible edges of objects. They allow depict the form of objects. Continuous lines also use for dimensional purposes. The use of line width for continues line is varies (Please see line width article for more detail).

Dashed lines represent concealed edges of objects, or elements that being removed for our view. I normally use dashed line with thin line width. Dashed lines also commonly use with thin line width.

Dot-dashed lines use for gird section line, building axes, centerlines.

Dotted lines indicate the edges of object lie above the cut plane in floor plan drawing or section plane. Since the dotted lines are difficult to see when we depict them with thin line width, I normally use medium line width for dotted-lines. I found it was difficult to use dotted lines when drawn by hand. Thus, I replace them with dashed lines instead.

Line Weights No.2: Implementation

I have written about line weights in the previous post of this blog. I would like to talk more about line weights in term of their implementation to drawings. Some may have a question about what the difference between line weights and line widths. They essentially are the same meaning but people use them differently. Most common use is the term “line weight”. In the history of making a drawing, we actually press the weight to a pencil to control the weight of a line. In the modern era, much of drawings are being produced via computational tools then drawings are being printed via printers. A printer controls the thickness of lines by using a width of lines to differentiate a thickness of lines. Therefore, the proper term for all lines that being produced via a printer should be called line widths.

Line widths play a significant role in architectural drawing. Without line width controls, we may not be able to effectively communicate the depth of drawings as we intended to. The examples above will offer you an idea and the outcome of drawings that is drawn with or without utilizing line widths as a method of conveying depth in building floor plans.

The image no. 1 is using a single line width.  Using a single line width makes the drawing difficult for a viewer to read the drawing and differentiate between solid matters and spatial voids in a drawing particularly when a drawing is a complex one. Therefore, using a single line width in drawings for communication purposes is not recommended.

The image no. 2 is using a hierarchy of line width to differentiate between solid matters and spatial voids. It is a commonly use in architectural drawings. The method helps facilitate the readability of a drawing very well when the line widths are implemented effectively. There are three line widths were used in this drawing: think (.35 mm or 1 pt), medium (.18 mm or 0.5 pt) and thin (.09 mm or .25 pt). I personally often use this method of convey the depth of my drawings because it is simple. However, this method may not work as we expected it if a drawing is created in a small scale (1/16″=1′-0″ closed to 1:200 in metric or smaller), particularly, when a viewer has to view this from a far distant.  Consequently, the method of conveying drawing depth in the drawing no. 3 is more appropriate for presentation of small scale drawing perhaps.

The drawing no. 3 is utilizing a technique called “poche”. It is a process of darkening the cut area of the solid elements such as walls, columns, etc. It is commonly used in building floor plan drawings and building section drawings..  Since the technique offers a strong contrast between spatial voids and solid element in building floor plan drawings, it is a lot easier for a viewer to quickly conceive the depths in the drawing. The poche technique in drawings is an ideal method of representation in drawings that are created with small scales, and being seen from a far distant likes presentation for a client in a meeting room with a group of people or pin-up situation in school project review.


One on the most fundamental part of drawings that help will strengthen the quality of each drawing is line weights (Some people prefer to use line widths).  Line weights convey depth and indicate various functions of each line in drawings. It is also portrays the appealing of drawings if line weights are assigned to drawings properly. I have been trying to explore the effective method of utilizing the line widths in architectural drawing (AD). I recently have come to the final conclusion of categorizing  line widths for both computational and manual methods of drawings in to three sizes.

-Thick line depicts cut edges of solid components:

Setting for computational method: 0.35 mm in metric, 0.014 in. in U.S measuring system. 1 pt. in graphic application

-Medium line uses for cut glass plane.

Setting: 0.18 mm., 0.007 in. and 0.5 pt.

-Thin line depicts visible, concealed, and projected edges

Setting: 0.09 mm., 0.003 in. and 0.25 pt.


Drawing is one of the essential elements in architectural design process. Either producing drawings by hand or computational methods, the essence of effective communication of design ideas in architectural design remains the same. It is a same principle with writing. The rules of syntax, spelling, grammar still apply to whether writing by hand on a piece of paper or using keyboard.  In architecture design, we utilize drawings as a vehicle of our thoughts, a communication of our ideas, and articulating our spatial imaginations.