In the 1950s, the psychologist J.J. Gibson outlined a number of cues to depth perception. A few rely on our binocular vision and therefore do not apply to 2-dimensional drawings and paintings. Others, however, are psychological rather than physiological in nature. As such, these depth cues are pictorial in nature and are applicable to drawing and painting on a 2-dimensional surface. In the following, I try to use simple terms and snippets of my own drawings and photographs to illustrate each of the depth cues that I consider to be relevant to drawing on location.
Convergence of parallels: This is a key characteristic of linear perspective in which parallel lines appear to converge as they recede into the distance. Despite the usefulness of the other depth cues, linear perspective remains the structural scaffolding upon which to build a sense of spatial depth on the page.
Overlap: Near objects overlap or partially block the view of objects farther away. Locating effective overlaps can be useful in selecting a viewpoint and composing a drawing.
Position relative to the horizon: Objects below our eye level rise toward the horizon as they recede; objects above our eye level descend toward the horizon as they recede.
Relative size: Objects known or assumed to be of similar size appear to shrink in size with distance from the observer.
Texture gradient: Surface texture appears to get finer and smoother with distance from the observer.
Shading and shadows: Contrasts in light and dark can convey the shape, form and depth of objects.
Aerial perspective: Particles in the atmosphere affects the color and visual acuity of objects at varying distances from the observer; distant objects appear grayer or bluer and less distinct than nearer objects.
As we can see, scenes more often than not comprise a number of these depth cues operating simultaneously. Seeing how these depth cues occur in our real-life perception can aid our understanding of why things appear as they do, counter to what we know of the things we draw, which are often in conflict.
While in Rio de Janeiro a month ago, we had the opportunity to visit Casa das Canoas, the first residence designed by Oscar Niemeyer in 1952. It is a true gem, nestled in a beautiful hillside setting and displaying the characteristic flowing lines of Niemeyer’s architecture. Thanks to Caique Niemeyer, Oscar’s grandson, for allowing us the privilege of touring this fine example of modern architecture.
After doing a few sketches of the exterior and interior of the deceptively simple structure, I attempted to draw a plan to try to understand the two-dimensional origin of what I saw in three dimensions.
To verify my plan, I perused several books on the architecture of Oscar Niemeyer but none contained a plan of this house. Upon returning to Seattle, I did an internet search and found this plan drawn by Jeff Hottinger, which is included next to the plan I drew.
In this age of digital 3D modeling where much design thinking and decision-making is made from a perspective viewpoint, it is still a useful mental exercise to try to imagine the orthographic relationships that plans and sections reveal and which perspective views do not. As designers, we should be able to think two-dimensionally as well as three-dimensionally.
Along with a few fellow architect-volunteers from the community service committee of the AIA Young Architects Forum, I met this morning with a group of middle schoolers attending the Northwest School Summer Camp. Our task was to introduce some basic drawing concepts to the young students. My topic was negative space, a concept that is somewhat difficult to grasp, especially when translating the in-between spaces that we see in real life into the two-dimensional shapes we draw on paper. After the session, I remembered an animation that I had created a while back when I was conceiving of a ebook on drawing. Here is an unedited version of Seeing Shapes.
Keep in mind that it is often easier to see shapes in a photograph and more difficult to see them when drawing on location from direct observation.
This measured drawing of the facades of the Oratorio dei Filippini (Oratory of Saint Phillip Neri) and the Chiesa Nuova (Santa Maria in Vallicella) in Rome was beautifully crafted by hand by Professor Emanuela Chiavoni of the Università Sapienza di Roma, who I met at the UID conference in Matera last year. Designed by Francesco Borromini and erected between 1637 and 1650, the Oratorio achieves a measure of strength and elegance not through decorative features but rather by careful proportioning and the use of opposing geometries, particularly of the interplay between the convex and the concave.
Professor Chiavoni executed this drawing as part of her Ph.D thesis and graciously presented it to me as a gift. The drawing shows the use of orthographic projection to objectively describe the formal and proportional relationships between the parts and the whole of a design.
Below is my drawing of the same facades that I had done while Professor Chiavoni accompanied me for an afternoon of sketching in Rome. These two drawings show the difference between the objective and perceptual descriptions of the same subject.
With the rise of digital photography color has become pervasive, unlike the film era where black-and-white photography was prized for its confident and raw visual style. In the field of sketching, too, color sketches are often seen as richer and communicating more information than monochrome drawings, which many consider to be primitive and lacking emotion. Yet, utilizing a range of strokes, black-and-white sketches can express a wider range of feelings than one might expect…
from light and airy…
to dark and heavy…
Much of my attention recently has been attuned to preparing the fourth edition of Architecture: Form, Space & Order. Working on this revision is giving me the opportunity to explore and attempt to understand the spate of irregular forms and compositions that dominate our consciousness.
Beginning a project is always enjoyable; thinking about all of the possible directions a work can take can be liberating. But beginnings can also be difficult when innumerable false starts interrupt the work flow and inhibit a sense of progress. I have come to realize, however, that these friction points are a necessary part of the creative process for they compel us to slow down, to pause, and to think ahead rather than simply charge forward into uncharted territory. One way I occupy these uncertain spaces is by roughing out ideas with a pen on paper and teasing out possibilities with a certain tactile rhythm. Here are a few examples.
Using the same broad outline of the Campo in Siena from two posts ago, I’ve overlaid the sketch with a diagram of the important points that I visualized in the scene—the extent of my view, the relative position of the Torre del Mangia, and the foreshortening of the Palazzo Pubblico.
To further illustrate the phenomenon of foreshortening, I’m using a plan diagram of the Campo to show where I stood as I sketched and my angle of view. You can compare the actual width of the Palazzo Pubblico, shown with the white arrow, with my foreshortened view of it, shown with the black arrow, and notice its position relative to the horizontal sweep of the Campo space.
You can also see, both in plan and in the perspective sketch, the positioning of the Torre about one-third of the way across from the right-hand edge of the view. I visualized diagonals to estimate the height of the Torre relative to the width of the space.
While these are necessarily optical judgments, not precise measurements, seeing these types of relationships and imagining them on the page as you set up a drawing on location are important steps in the process.
Foreshortening is the apparent change in form an object undergoes as it rotates away from our point of view. This phenomenon is usually seen as a contraction in size or length in the direction of depth, the amount of contraction depending on the degree of rotation. The more a line or plane is rotated away from our point of view, the greater its apparent contraction. You can easily see this as a door opens away from you. Gauging and drawing the phenomenon of foreshortening can be a bugaboo for sketchers because our mind can persuade us to draw what we know—the actual size or length of something—rather than how that thing might appear to the eye—its apparent size or length.
To illustrate a case of foreshortening I want to use this view of the Virginia V that I sketched this past Sunday before the Seattle UrbanSketchers group met at the Museum of History and Industry for its January meeting. One of the reasons for gathering at MOHAI is the beautiful exhibit there of Gabi Campanario’s impressive work documenting the life and times of Seattle over the past six years for the Seattle Times.
The Virginia V, built in 1921 by Anderson & Company and launched in 1922, was part of the mosquito fleet that plied the Puget Sound waters largely between the First and Second World Wars. After WWII, the Virginia V changed hands several times as it served as an excursion vessel. It was placed on the National Registry of Historic Sites in 1973. Completely refurbished by the Steamer Virginia V Foundation, the Virginia V is now anchored at the south end of Lake Union and continues to be used for public excursions and private charters.
In this view of the same Virginia V sketch, I’ve overlaid some markers to show the relationships that I gauged and used to control the foreshortening of the ship. The most important step is ensuring that the apparent length—from the prow on the left to where the hull curves away from our view on the right—is correctly foreshortened relative to the height of the prow. Then, I positioned elements, such as the wheelhouse and bridge, relative to the left and right extents. Note how I try to suggest the way the hull is curved from fore to aft. You can use the span of your hand, the shaft of your pen or pencil, or any similar means to gauge these measurements but it is an essential step in the process. Otherwise, your mind will strongly suggest that you should draw what you know rather than how it appears to the eye.
When an architect, designer, or builder says that a building has “good bones,” this generally means that it is well built. Like others, however, I would extend the meaning of the phrase to include not just the sturdiness of a construction but also the soundness of its underlying organization and layout. A design with good bones should be able to endure flaws in workmanship or execution and gracefully accept the changes made to improve it.
So it is also with a sketch. To begin a drawing done on location, we must first select an advantageous viewpoint that conveys a sense of place and frame the composition to fit on the page. Then, a crucial step is establishing the “bones” of the drawing—its basic structure—with the first lines we draw. I like to say that the number of lines is five but this, of course, is arbitrary. For some views only a few lines may be necessary while for others, more might be required to establish the structure of a drawing.
It is essential to understand that once this structure is established, changes can still be made to calibrate scale, improve proportional relationships, and adjust the positioning of elements. Drawing these first few lines is simply a way to block out the essential relationships on a page quickly, before expending too much time on a drawing only to find out that a portion might be misplaced or is out of proportion to the rest of the composition.
Here is an example—a very quick outline of a view of the Campo in Siena that I did as a demonstration. With more time and better weather, I might have finished it but I think it is possible to see and visualize the space even in this incomplete state.
Standing in the courtyard of San Pietro in Montorio on the Janiculum Hill sits this almost ideal example of Italian Renaissance architecture by Donato Bramante. What makes classical architecture such as this beautifully harmonious work so difficult to draw is that any slight deviation from the intended proportions becomes very noticeable. I’ve attempted to draw the Tempietto several times and I still haven’t got it quite right, although this one comes close. It’s just a little too tall for its base.