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Start your free trial. Drawing for Product Designers by Kevin Henry. Book description This is both a practical and theoretical guide to the visualization techniques used by contemporary product designers, including freehand sketching, digital rendering, information graphics, and presentation skills.
Show and hide more. Table of contents Product information. Understanding Sketching 2. The Psychology of Sketching 3. You might also like video Python Fundamentals by Paul J. Self publishing. Share Embed Flag. TAGS download ebook designers ebooks audiobook portfolio visualization rendering sketches audible.
You also want an ePaper? Hundreds of hand-drawn sketches and computer models have been specially created to demonstrate critical geometry and show how to develop sketches into finished illustrations. Practical tutorials give guidance in creating simple and complex forms, as well as rendering and providing context using scenarios and storyboards. Insightful case studies of leading designers illustrate the full range of different visualization options available.
Share from cover. Share from page:. Flag as Inappropriate Cancel. Delete template? Are you sure you want to delete your template? By removing the mirror he quickly sees the actual structure.
Returning the mirror he can compare the painted image to the reality. Here, Brunelleschi has positioned himself directly in front of the octagonal baptistry building at precisely the correct distance so that his painting of the baptistry corresponds with the actual building. In his right hand he holds the painting with the back facing him and a small hole to peer through.
Chapter 1 Understanding Sketching 17 Innovation Brunelleschi demonstrated the existence of a direct link between human vision and projected reality. The image coming into the eye cone of vision corresponded to the network of lines receding to a central vanishing point. As the viewer changes orientation, the network of lines changes accordingly. Perhaps the most astonishing thing about this book is that it contains only text.
While Brunelleschi relied largely on drawings to prove his method, Alberti, who was trained as a lawyer before turning to architecture and the arts, relied entirely on textual descriptions.
The illustrations that appear in modern translations were subsequently added as an appendix. They provided a mathematical language for describing geometry— point, line, and plane—in addition to a repeatable method for creating regular forms such as equilateral triangles and polygons.
These simple descriptions were used to develop more complex axioms and propositions. The octagonal plan of the baptistery makes it relatively easy to draw using Florentine workshop methods based on grids.
A line, therefore, might be considered one dimensional; a plane is two dimensional; a volume is three dimensional. A line has only length; a plane has length and width; a volume has length, width, and depth. The curved line is not straight from one point to another but rather looks like a drawn bow.
More lines, like threads woven together in a cloth, make a plane. These intersecting points are projected across to intersect with the orthogonals that recede back to the vanishing point. Change the vantage point angle of view or the distance from an object and the image changes with it see left illustration.
The cone or pyramid of vision is illustrated in red. Changing the distance or orientation of the object or the viewer vantage point changes the image on the retina of the eye. Chapter 1 Understanding Sketching The Italian painter and mathematician Piero della Francesca —92 further consolidated the ideas developed by Brunelleschi and Alberti, adding greater rigor and method. A kind of hinge exists between the orthogonal and perspectival planes, around which the orthographic projection swings into perspectival space.
The diagonal in conjunction with the single vanishing point makes all of this possible. Before reaching the vanishing point it intersects the top diagonal, which is then projected orthogonally.
This orthogonal line will intersect with the second projection of the same point to form a nodal point of intersection. This process is repeated for every point.
His deep understanding of mathematics and geometry, combined with the practical experience he gained in Florentine workshops, allowed him to connect perspective more directly to orthographic projection.
Innovation Piero established a clear and mutual relationship between an orthographic view hinged to a perspectival view via the diagonal. Critical points in the orthographic view are projected through vertical and horizontal lines along the diagonal up to the perspectival plane where they are accurately mapped in space. This process is about speed over accuracy. This primitive perspective machine required two people to operate it.
One of them held a taut piece of string connected to a pointer or stylus at any point on an object while the other moved a type of crosshair, or adjustable set of vertical and horizontal strings, to mark each coordinate within the frame. Once the crosshair was set the string was withdrawn and the window closed, so that the point could be pierced into the parchment, thus creating an accurate constellation of points by which to map the object. Chapter 1 Understanding Sketching 21 Drawing involved connecting the dots; a process described earlier by Piero della Francesca where the rays are lines and the eyes are points.
Innovation When viewing objects in a natural setting or in a built environment such as a building or other structure, the vanishing points will converge on the natural horizon line. This same horizon line will cut through the eye level of every person standing in the landscape, regardless of how far away they are see bottom picture. This approach can be thought of as a precursor to early CAD programs where points are physically plotted in space with a pen tool.
Notice that the grid lines are not uniformly spaced but are consistently projected from view to view. Below Perspective is so consistent that similar height objects or people can be scaled simply by referencing the horizon line.
In the example below the horizon line passes directly through their eyes. Chapter 1 Understanding Sketching 23 Leonardo da Vinci, perhaps more than any other artist of the Renaissance, used sketching to record not only what exists but also to explore and explain what might exist were it more visible. His research into the nature of light, shade, and shadow helped him to better visualize the world in his paintings and frescoes while adding greater depth to his illustrations of the human body and complex machines.
His inquisitive mind put sketching to the task of understanding and recording anatomy, hydraulics, projectiles, motion, and the makeup of the eye itself. Idea Leonardo da Vinci not only mastered perspective sketching but was also able to leverage all forms of quick visualization—perspective, orthographic, section cuts, details, etc. His notebooks remain the quintessential example of creative sketching.
But he also made important contributions in the areas of light and atmospheric effects on vision that continue to affect the way we sketch and render today.
His drawings are the essence of design visualization, relying as they do on orthographic, perspective, and quickly scribbled notes. It was, however, primarily a technical feat. Students struggle with this integration and often treat the acquisition of sketching as merely a technical skill; one that even gets in the way of being creative.
In fact, sketching has to be fast, cheap, plentiful, suggestive, and exploratory just like thinking, which, as it turns out, is a very visual process. Even commonly used metaphors and analogies employ visual and spatial attributes to provide us with a quick and easy context in which to communicate and build thoughts. Thinking, like seeing and sketching, is a constructive process. A bowl is really a deep plate or, conversely, a plate is a shallow bowl. A cup is a more intimate bowl with a handle affordance for grabbing and holding.
Our brains recognize the particular as a variation of the general. The main difference is the vantage point from which they are viewed. Survival in evolutionary terms has required us to project our senses beyond our immediate bodies. Such a survival mechanism brings with it the added ability to imagine or consider things that are not physically in our hands or within our sight but which instead reside in our heads our library of forms.
Psychologist Michael Leyton refers to this as a generative theory of shape. But how does the psychology of seeing directly impact the process of sketching or visualizing ideas? The mechanics of vision: several theories The incredible speed with which the brain interprets information millisecond makes it impossible to observe ourselves seeing, but nevertheless our brain, in conjunction with our eyes, is actively constructing perceived reality out of all the data that comes in: seeing is anything but a passive activity.
To recognize is to see familiarity in things through a repeated occurrence or a pattern family resemblance for example. But what exactly is a pattern and how do we detect one? Ode to Joy in C major 4 4 Ode to Joy in E major 4 4 Chapter 2 The Psychology of Sketching Gestalt psychology Gestalt psychology began in Germany, in the early part of the twentieth century, initiated by a group of psychologists who explored the visual and cognitive mechanisms behind pattern recognition.
Wertheimer exited the train at Frankfurt, purchased a toy stroboscope and began conducting simple experiments with various drawn lines which, when revolved, created the illusion of motion. While Gestalt psychology deals primarily with static two-dimensional patterns it is important to remember that sketching is a 2D pattern of a 3D representation.
When placed in a zoetrope or in his own invention, the zoopraxiscope his photographs anticipated motion pictures, yet no one could explain why until the Gestaltists began their experiments decades later.
Good Continuation: objects that suggest movement are related. These photographs are examples of texture gradients, surface details that allow animals or humans to pick up real information from their environment—judging distance, for example, or even seeking out places of shelter from predators. While Gibson embraced and admired the work of the Gestaltists, he soon developed his own theories focused less on static imagery and vision and more on the dynamic interactions between humans and animals and their natural surroundings.
Gibson began to develop what he termed an ecological approach to visual perception, pushing the psychology of vision past the static pattern-detection of the Gestaltists into the new and more dynamic realm of motion.
Humans decipher space based on depth cues, and the texture gradient is similar in a sense to the orthogonals and transversals employed by artists such as Piero della Francesca and Paolo Uccello to suggest accurate depth perception. The texture created by the patterns creates what Gibson called a texture gradient, and signals to our brains that the smaller the stones, the further away they must be.
The brain constantly assesses information as we move or as objects in the environment move: if the convexity were an enemy bunker a pilot would need to be at a lower vantage point to detect it.
If our brains understand the invariance of objects they can certainly be of assistance in imaging what something might look like when viewed from different angles when sketching. Again, it all comes down to rules. Optical occlusion refers to the phenomenon whereby the edges of an object that are not viewable by the eye are still understood by the brain to exist. These occluded edges become the ghost lines of quick sketching see chapter 7.
They are a part of nature: they do not have to be visible. The manner in which our brains interpret the world of objects is essential to the way in which we represent objects. They clearly communicate their underlying structure and form through the power of gradients. The wireframe from an earlier iteration of the serving plate shows the power a gridded set of contour lines has to represent a similar form without any gradients.
When the two powerful tools, line and rendering, are combined the brain is very easily convinced that what it is seeing is three-dimensional. Quick sketching relies on both these skills. Photographs by Lara Kastner.
Whereas Gibson focuses heavily on reading and comprehending surfaces, Biederman is more concerned with an underlying set of shared structures. His recognition-by-components theory, while largely discredited, remains very useful as a metaphor for sketching and thinking about form more generally. The idea is quite elemental: a group of idealized geometric shapes known as geons—short for geometrical icons are stored in the brain for comparison with what we see in the world.
This process of intersection commonly occurs in computer-aided design and involves Boolean operation. Such strategies will be explored in greater depth chapter 6, Shape Morphologies; chapter 8, Exploring Forms in Space. Edwards believed strongly that her drawing students could shift from what she called the L-Mode to the R-Mode and in the process free themselves from the natural tendency to logically identify verbalize what they were looking at: to see the world rather than name it. The juggling that has to occur between these acts gets to the heart of what design sketching is all about.
When we look out into our environment everything appears to be crystal clear when in fact our eyes are only focusing on a very narrow sliver of reality approximately 2—3 percent. The dimensionality of this plane is restricted to the up-and-down and side-to-side axes—height and width.
Chapter 2 The Psychology of Sketching 35 up left right down Fig. Objects and patterns must be discovered and binding is essential because it is what makes disconnected pieces of information into connected pieces of information. And conversely those things in our path that we are not interested in simply disappear. The optic nerve, however, is a relatively small pathway so the incoming signals have to be spatially encoded or compressed before being sent via the ganglion cells to the primary visual cortex.
This compression process, which occurs in the retina, involves enhancing the edges of the object, much like photomanipulation software might sharpen or enhance the edges of a shape or region in a photograph.
It is in these streams that the biological signals work together to identify objects in space through being either excited or inhibited. The process is a quick but incremental one with the initial inputs moving through the visual areas along the ventral stream to arrive at spots deeper inside the brain. Knowing when to close the hand around a desired object when picking it up off a table may seem mindless but a tremendous amount of machinery is in place to make this feel effortless.
Even the experienced designer with good sketching skills exerts a great deal of mental energy to shape thought based on quick and provisional marks in order to build meaning where there is currently none. The pathways are critical to recognition, but also to committing an action like reaching for a knob or lifting a pen to sketch. The right amount of ambiguity allows even the designer to see possibilities that may not have been intended.
The competent quick sketch is read as an idea in motion rather than a fully resolved idea. Chapter 2 The Psychology of Sketching 37 Fig. Bad ambiguity tends to come down to mechanics, and how we see and interpret drawings. An overview of classic forms A good place to begin reviewing bad ambiguity is with the classic forms named after the scientists who developed them, such as the Kopfermann cube, the Necker cube, the Ponzo illusion, and the Rubin vase.
There is no differentiation between the foreground and background—another crucial Gestalt principle. The lack of receding lines and variation in the line weights contributes greatly to the object being ungrounded. Some of the impossible drawings for which the Dutch artist M. Escher is famous come out of similar manipulations. Front top edge in direct alignment with bottom back edge Front top edge in direct alignment with bottom back edge Front top corner overlaps with lower back corner Front vertical edge in direct alignment with back vertical edge Fig.
Highlighting the corners or darkening a plane adds greater stability and thus makes the image easier to read. The power of receding lines cannot be overestimated. The power or context of the receding lines to suggest depth makes the top one naturally appear larger and longer. The superimposed red rectangles are identical in both length and height, yet the top one appears both longer and wider because of our natural tendency to read depth when we see receding lines.
Context in sketching and drawing can be just as critical to comprehension as it is in a photographic image. Depth cues like the receding lines of the road, the diminished scale of the clouds, the cast shadows, and the horizon are all natural cues that provide context. Chapter 2 The Psychology of Sketching 41 Context is vital to good ideation sketching, whether in the form of a cast shadow which literally grounds an object or a hand holding the product, or a vignette to frame it.
The fact that the background forms a recognizable shape only confuses the issue further. Until either the background or the foreground becomes dominant the brain will struggle to determine depth.
In this chapter we will begin by exploring various manifestations of sketching and end by looking at the many ways sketching has been impacted by the grid. A good quick sketch conveys enough information to be interpreted while leaving a lot to the imagination of the viewer including the designer. Barbara Tversky has noted the existence of similar graphic inventions among many preliterate cultures and points out that many of these same approaches or preferences are naturally employed by children.
Dan Roam, author of The Back of the Napkin, notes that nearly every child in a kindergarten class will raise their hands when asked if they can draw; ten years later only three of the children will raise their hands.
However, the issue for designers is how to leverage both the visual and the verbal skills, since each has its own powers as well as its own shortcomings.
For example, iconic drawing as a communication tool fails in capturing nuances beyond people, objects, and simple activities. Attributes and relations, for example, are hard to represent because they are abstract: preparing hot food Fig. The designers have added color and type hierarchy while reorienting the overall direction to align it more along the natural left—right direction required when reading English. Single sketches lack the subtlety required to explore the temporal or even causal, which are better expressed through sequential sketches or rough diagrams.
Of course, children are less concerned with the clarity of communication in their drawings even as they intuitively manipulate the spatial relations of hierarchy, scale, and distance along with color or line characteristics to create rich and dense images. These skills clearly lie dormant in us, waiting to be reawakened and utilized not as childlike drawings but as images that merge the power of quick and simple sketches with the sophistication of language and writing.
Combining the power of verbal and visual languages to communicate among varied stakeholders to arrive at clear visualizations. Image copyright Dan Roam www. Metonomy, for example, allows a part to represent the whole all hands on deck ; a synecdoche relies on a symbol to represent the whole a crown for the royal family. Good diagramming relies on these types of shorthand method to ensure speed while not getting bogged down in details that are not necessary for quick communication.
Rough diagrammatic sketches can be further scrutinized, revised, and appended before being turned into a more polished diagrammatic drawing. Even at this stage decisions can be made to increase clarity, add new components, or otherwise revise. Diagramming involves broad and generalized thinking that focuses on larger and more abstract issues such as organizational structures or the interaction of multiple inputs in a system as opposed to the actual appearance of things.
Because the eye is not constrained by the horizontal lines of a ruled book, it can scan diagrams in a way that is similar to natural vision. While diagramming may seem less accomplished than realistic sketching it is really just a different kind of sketching.
It can assume many forms including what is commonly referred to as a wireframe sketch, for a website or interactive device. This is the least ambiguous view and does not attempt to suggest illusionary depth.
The orthographic view also has natural cognitive attributes that make it easy to understand, much like a map. The considerations that go into a time-based interaction are very different to those for form-based sketching but it is increasingly important for product designers to understand and master them. Reading it can reveal whether the person was wearing a shoe or walking barefoot, the general direction they were going in, their approximate weight, the speed of their gait, and roughly when they passed by.
Diagramming is clearly part of the original human impulse to communicate: to document the hunt so as to organize the group effort. It is not a great mental stretch to imagine the footprints of animals in the snow, sand, or wet soil serving as an early model for sketching and diagramming the direction from which they came.
As hunters, our species had to learn to interpret such information. Our hunting origins may also explain why the arrow has become such a universal symbol of direction.
Nature has an arsenal of tools for creating meaningful marks which we constantly read and extract information from, including the tides of the ocean and wind-sculpted patterns in sand dunes. Our eyes and brains are exquisitely tuned to extract the information required to make sense of the world projected onto our retinas.
On the microscale of sketching, edges, nodes, paths, and regions factor into the way we read and create sketches. Edges correspond to the outlines of objects; nodes correspond to corners where multiple vertices intersect; paths can be thought of as the interior contours within an object; and regions as the individual parts that make up most products buttons, attachments, switches, caps, etc.
Patterns, line weights, and colors to help us distinguish larger regions from distinct arteries like thoroughfares, boulevards, or common roads. For this we must rely on shade, shadow, and gradients to create the necessary illusion of depth.
These tales epitomize the power of both sketching and modeling. The explanation of the power of lines is that they are effective in stimulating the generalized contour mechanism. Even though we are looking into a three-dimensional world, it is faster and less resource-intensive to scan the surface of the image plane up and down and left to right, and mentally construct the depth information from depth cues, edge, texture and color boundaries, and light cues.
Physical prototyping not shown here is also an essential part of this process. The power of drawing conventions Sketching and drawing rely on the power of conventions—common rules and procedures established by a community of users to facilitate quick exchange— just like language.
And while language conventions continue to evolve subtlety due to the abstract nature of spoken and written words, drawing conventions, based as they are on perception and geometric construction, have had centuries to cohere. The three most common drawing types are orthographic, isometric, and perspective.
Additional conventions like section cut and details make drawings easier to comprehend. Sketching relies on these same conventions although it is done more loosely with less attention paid to accuracy. Isometric and perspective are clearly the most related, but it is orthographic that allows for the accurate dimensioning of an object, space, or structure for purposes of building or fabricating. All of the systems rely on projection. While it is not representative of the way humans actually see objects, there is no distortion, which means the various views can provide accurate dimensional information for construction.
The convention minimally displays a top, front, and side view which are aligned. Orthographic will serve as the foundation for teaching perspective throughout this book.
In isometric the three primary planes top, front, and side are visible and parallel lines on the object are depicted as parallel in the drawing. Isometric variations, like axonometric, result from the angle of rotation away from the primary picture plane.
In perspective the three primary planes top, front, and side are visible and all lines parallel on the object recede to either one or two vanishing points situated on the horizon line. While three-point perspective is possible it is less common. Perspective is excellent at representing the world as we perceive it; however, it is ineffective at accurately communicating dimensions. Slicing an apple in half produces a section cut.
It had been fundamental to the Greek geographers Hipparchos in the second century BC and Ptolemy years later in their quests to measure and map the world longitudinal and latitudinal grid , and it was equally fundamental to Piero della Francesca in translating geometry from front view into perspective.
Art historian Hannah Higgins The Grid Book points out just how central the grid has been to the measure of everything from the unit of building the brick to the organization of cities gridiron to the primary metaphor of our networked world the internet as an informational web. Today most software relies on grids, whether for graphic, text-based, or computer-aided design programs. In order to create an accurate illusion of diminishing tiles in space, the vertical lines projected from the central vanishing point must be intersected by additional lines projected from vanishing points to the left and right.
These intersection points mark where the horizontal lines orthogonals will be placed. The way the grid works is to consistently subdivide space into ever smaller vertical and horizontal increments, thus creating a uniform mesh. Artists have long used the grid to transfer drawings from one surface to another, and to scale small sketches up simply by changing its unit measure.
A standard procedure places one set of criterion along the vertical Y axis and another along the horizontal X axis to visualize two interlinked variables over time. The coordination between eye and brain is reinforced through an awareness of the underlying gridded space, and as skills increase the grid can disappear slowly and serve more as a ghost grid for projecting symmetrical points across centerlines to build form quickly and accurately.
Cartesian space, as it has come to be known, is a uniformly gridded space in two or three dimensions with numerical values overlaid on top of the grid. Anything set into this space, whether two- or three-dimensional, can have an exact set of coordinates assigned to it based on its distance to the origin the intersection of all axes. A circle with its end point at the origin 0,0 and its other point two units away visually reveals points along its circumference.
CAD relies heavily on this capability. The street sign is an example of a Cartesian axis. The Cartesian co-ordinate system is like a set of city street signs projecting off a pole; one street is the x axis, one is y, and the pole is z. The Cartesian axes correspond to the three dimensions of length, height, and depth. The raster grid digital photography Fig. The grid also makes digital imaging possible. A digital image is a mosaic of tiny identical squares, each assigned one color to simulate the actual photographic image.
When the squares are small enough higher resolution the eye cannot detect this mosaic pattern and instead sees a normal photographic image. The mechanics of vision: eyes and camera The human eye, while a great metaphor for lenses of all kinds, captures information differently to a camera.
These signals are delivered to the primary visual cortex where the edge detection process described in chapter 2 begins. The camera lens, unlike the eye, has to be mechanically or electronically manipulated to change focus. Digital cameras rely on circuits, lenses, charged couple devices, and LCD screens to display the image. The biggest difference between human vision and the mechanical vision of photography is that humans posses two eyes binocular while the camera has only one monocular.
Two eyes make depth perception possible. The challenge is learning to train the brain to represent or visualize in the same way that we perceive.
This involves internalizing phenomena like foreshortening and projection, which we will cover in depth over the next few chapters. This is explored in detail in the tutorial on orthographic projection at the end of this chapter p. A sketch or drawing is therefore very much like a photograph even though a human with binocular vision produces it. The edge of the glass closest to the viewer is clearly shorter in length than the similar edges further away or oriented differently.
The initial sketches are a part of the analysis process. Color and scale is used in the model to encode key types of data. The original hand-drawn matrix used numerical ranking and color to sort the competitors. To begin the process, one view must be known top, front, or side view for example. The projection process can begin from this known view, moving at degree angles horizontally and vertically.
Side view Front view 1. Begin with the dominant view of the object— in this case the side view. Project lines from vertices end points in both the vertical and horizontal directions.
Side view 3. The dimensions of the front view must be determined beforehand. Sketch vertical lines to meet existing horizontal projection lines from the side view. Top view 4. The remaining network of intersecting lines reveals where the last edges are to be placed. Networks like these can be confusing. Reference each view for help. Mentally moving between the three views helps construct a three-dimensional understanding of the object. Orthographic views are used for dimensioning objects.
With darkened bold outlines the outside edges stand out. Their strength comes through the ease of dimensioning. Equally important is the fact that anyone can extract dimensions with a scaled ruler.
In the perspective drawing each plane has been assigned a number from 1 to 3 and color coded according to the view it is associated with. This has been transferred to the orthographic views. Note that only the front view has more than one color because of the sloping plane. The perspective drawing enables an immediate understanding of the object but is not ideal for dimensioning.
Depending on the complexity of the geometry the process might initially require a single view. Most often designers will develop two views simultaneously; for example the dominant view along with one of the secondary views.
In other situations three views are required to really understand the form. In the case of this utility knife the dominant view side view is the primary focus.
The range of sketches have been included to show that a designer does not really need to know what the product is going to look like in the beginning but needs to start somewhere and build through iterations. Think of the below as a selection of crucial key frames in a much longer sketch animation.
The step-bystep process on the following page shows the projection process for all three views even though a single view or a two-view is often enough.
Begin with the simplest of layout lines to suggest the overall footprint of the product. In this case, the bend in the body of the product is indicated with straight lines although curves will be sketched over these lines. The projection lines have been drawn with a ruler but usually such sketches are done entirely freehand to keep the process moving.
Two views are often enough to get started front and side view. All three have been included here to clarify the interrelationship between views.
Over these more expressive lines or arcs can be accurately sketched. The projection lines help to register the geometry in the various views while assisting the designer in accurately shaping the product from multiple vantage points. They can be developed together. Secondary detailing can begin once the overall volume of the product is established.
Much like the initial layout lines, secondary details like the grips in an overmolded handle can be lightly and quickly sketched for possible placement. The whole point of this approach is to quickly place geometry knowing that it can just as quickly be changed or altered. Note that not a single view is complete at this point: all three views are slowly being built and cross referenced.
Additional details like the blade release button and the blade carrier assembly are sketched to help accurately locate other components. Line weights need to be adjusted. In this case a new sketch would be started with the original sketch as an underlay to help facilitate the process.
The outline is the darkest line and should serve to unify the body. Ghost lines can be left like the blade assembly or removed entirely. Details like the grips on the button are added to the top view where they are easily read.
Once the projection lines are completely removed the three views are much less obstructed. The front view has not been completely cleaned up. It is by far the hardest view to sketch accurately and less useful than the other two views given the extreme foreshortening. Nevertheless, any work done of any of the views makes perspective sketching that much easier because the geometry is familiar.
Direction and point of view determine the way we perceive objects and spaces, so attention paid to these will lessen bad ambiguity. Context is another critical factor; a common mistake is to sketch an object in an unusual orientation because this is the easiest way to sketch it. Directionality relates to the dominant and subordinate orthographic views commonly associated with objects.
For example a car or chair is more recognizable from the side view than from the front or top view. For this reason, designers often make thumbnail sketches in the dominant view, to get ideas out quickly and establish key proportional relationships before adding in a subordinate view.
When sketching in perspective the product should be positioned so that dominant and directional biases are emphasized. For the same reason, symmetrical objects like bottles, plates, or light bulbs, which have neither strong directional biases nor dominant views other than front and rear labels , are not as affected by orientation.
Adjusting the point of view where the viewer is standing in relation to the product has a big impact on how a sketch will be read. This relates directly to the orientation of perspective or isometric drawings as they show multiple sides of an object simultaneously.
The ghosted-in centerline helps reinforce the main axes. Both isometric and perspective position the viewer so that three faces are seen simultaneously. Orthographic views emphasize proportions and dimensions while isometric and perspective emphasize three dimensionality. Projection, however, is part of all the drawing systems and is therefore crucial to sketching and drawing. Projection occurs in many ways: a line is a projection between two points; a plane is a line projected into space; and complex surfaces are the result of projections between sectional sketches.
Sectional sketches are connected by projecting a 3D curve from section to section to enclose the primary surfaces that make up the stamped metal trowel and the plastic handle. Understanding the many ways geometry can be projected requires understanding what makes up geometry: points vertices , edges, and faces surfaces.
Dialing from an upside-down orientation requires conscious thought. A good sketch or drawing has to account for all this geometry while the sketching process should, technically speaking, create it. Front view Side view Fig. Vertices Chapter 4 Orientation 69 Fig. The individual projection process is analogous to tracing each face of the object directly onto a sheet of paper. This type of geometry requires the designer to know where outside boundary edges and internal edges lie within the object, and project those that are perpendicular to one of the primary planes.
If there is internal geometry it, too, must be projected. These ski goggles show a plane passing through the center of the product. The challenge comes when the faces of the object are not parallel to the primary faces or when they are curved or compound surfaces. Isometric projection creates an illusion of three-dimensional geometry. However, because all similar edges and faces remain parallel, the appearance is less than realistic; it hovers between the accuracy of orthographic and the illusion of true perspective.
Cognitive scientist David Marr referred to isometric as 2.
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