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In engineering, fabricating, and all-around making, it is very useful to know basic drawing styles. This will help you get your ideas out of your head and onto that napkin, or into your notebook so that you can bring them into the world. Architects, planners, designers, engineers, and others use drawing to help communicate their ideas clearly and accurately to the people who will carry out their designs. Drawing is also a great way to communicate with yourself, since you can draw a picture of it to help clear up the parts of the idea before moving to the next steps of your design.

Here are a few drawing techniques that will help you speak in a common visual language:

Orthographic
If you’re thinking in terms of a floor plan, or a straight-on view to an object’s face, that’s an orthographic view. In this technique, you are showing the details of the face, where the edges are, if there are holes or visible cuts in the surface, you would show them as solid lines. If those holes or cuts are in another face and not visible from your viewpoint, they would be shown with dashed lines.

An object could have six Orthographic views, top, bottom, right, left, front and back. One way to help visualize the six sides is to take a cardboard box and cut windows in each of the sides. Label the sides and place an object inside the box. When you look straight at the object on one side, that is the view you would draw. You wouldn’t try to include any information from another side.

Multiview Orthographic
Sometimes, you will have a complex object that has information on more than one side. You will want to show the relationship between the sides in a mutltiview orthographic drawing. Here, what you want to do is line up usually two or three corresponding views. Normally, you would show the top view above the front view. The features of the object visible in the top view would line up with the features in the front in a two view drawing. If the side also has details, you would draw the side so that it lines up with the front view.

Isometric
So, you want to show several faces of the object, but don’t want to make a whole bunch of individual drawings. You want to know about Isometric projection! This technique has you placing the object at an imagined 30-degree angle and drawing the three faces that are visible. In isometric, all the sides have parallel edges, just as they would in the real object. The object can be drawn accurately enough to pull measurements. Since three sides are visible at once, you can get a real sense of the object by looking at the drawing.

Scale
If you hope to build directly from these drawings, you’d want to do them accurately and with a scale in mind. There are many different scales, or ratios of drawing to object available to you. Some are pretty simple, like 1:1, full size, 1:2 or 1/ 2 size or 1/4 size. There are lots more, and rather than figure out how far apart to draw the marks to accurately show 3 inches in 1/4 scale, you can use an architects’ or engineers’ scale, which translates feet and inches down to the smaller scale. When you are drawing to scale, a person could put the corresponding scale right down on your drawing and pull out the measurements, which should match your notations.

Sketching
If you just want to get your idea out of your head, sketching is the way to start. Here, what you do is take your paper in hand and draw out your idea using one of the techniques above. With sketching, it is more about the speed of showing your imagined or observed shape than precision and accuracy. Usually, with sketching you would only use a pen or pencil on the paper. The straightness of the line comes from your hand, not from using guides. Get the idea out. You can refine it through revisions, bring it into a drawing program, draft it accurately with drafting tools, but all that comes later, after you have put it on the page. Sketching is quick and helps you see the relationships of the shapes and parts.

Looking for more? Try out the simulation at the bottom of the Teacher Support page of the Engineering the Future curriculum from Boston’s Museum of Science. In Sketchup and other Computer Aided Design programs, you can go to the view menu to see each of these views. But really, the best way to build this into your head is to pick up a pencil or pen and start drawing. Draw the objects on the table in front of you, one at a time. Show them in orthographic, multiview and isometric. There are drawing papers available with square and isometric grids printed on them to help guide your drawings.

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Chris Connors

Making things is the best way to learn about our world.


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Comments

  1. Joe says:

    The example isometric drawing is really really poorly done. I’m speaking in a technical sense as a draftsman, but it fails even the look at it and see what it is test. I mean, there are no two lines that are even close to parallel.

    It’s an example of a bad sketch and not an isometric drawing.

    I doubt that the author has ever taken a drafting course because otherwise, he would know the purpose of putting the orthographic views around the isometric projection in the way that is shown.

  2. oskay says:

    Joe: Your criticism is not– in any sense –helpful. If you have a better example to link to, that might be appropriate.

    Maybe Chris took the course in good manners while you were in drafting class?

  3. tenax8.myopenid.com says:

    I mean, if we’re going after pure drafting technique, there are no dimensions, no material callout, no surface finish indicated, or anything that might help this part get made, not to mention that that internal corner is going to be a bitch to make. However, it is a fine sketch and it does get the idea across, which is all that is necessary at this level. Besides, maybe the sides aren’t supposed to be parallel; maybe it’s the orthographic projections that are incorrect!

    I am an engineering student, and let me tell you that drawing by hand is becoming a lost art. All the drafting software we use generally makes the drawings for us, but watching most of my fellow students try to convey an idea on a napkin is like watching someone try to moonwalk on carpet in sneakers.

  4. Anonymous says:

    When I read this post I didn’t choose to believe that the drawing in the maker notebook was intended as an engineering drawing as a source for manufacture. Nor did I expect it to be the perfect example of draftsmanship.

    It is a sketch in a notebook. Its purpose was to be photographed for this blog to help illustrate this blog post. It certainly could have been drawn better, but it served the purpose – that of a notebook sketch intended to illustrate (better than crudely) orthographic/isometric drawing.

    So the drawing might get an F for the ability of anyone to manufacture this part (which was not the purpose of the drawing) but an A- for the real purpose of the drawing: Illustrating this article.

    (The minus, because geez man connect your lines! :-P )

    1. Chris Connors says:

      Above, you will see that I revised the image, this time using a ruler to ensure straight lines. The original photo is here. While the first drawing was intended to show a visual for each of the techniques, it was also supposed to be a quick drawing using a minimum of tools. I found that doing the same drawing with the aid of the pencil and ruler slowed me down, and helped me make a much neater drawing.

      Sketching out your ideas can be a great way of moving them out of your head and into the world. Often your preliminary sketches can be brief and quick, while at the same time allowing you to flesh out the concept better.

      How do you use drawing in your making? If you are willing to share your notebook, take a photo and send a link.

      Chris

      1. Anonymous says:

        You shouldn’t have caved in to “Joe”. Your first drawing fit its intent sufficiently.

        You were drawing in your _notebook_, not on drafting paper. You sketched freehand. Your effort got your point across.

        I would hope that if the intent of the drawing were to get a part machined, that there would be more effort than a freehand drawing, but your original drawing wasn’t meant to be any more than it was. It didn’t need to be. And, honestly, for a freehand sketch you did quite well.

        Now before I ask what is on page 20, I need to go off and beat my child for coloring outside the lines…wait I’m not Joe.

      2. Joe says:

        I appreciate your changes. I think it looks much better. I don’t remember exactly what the original drawing looks like anymore, but I definitely think that this edit is a big improvement. Like, if I recall correctly, from the old isometric drawing, it was hard to tell that the rear half was a perfect cube, and the front half a partially dissected cube, but with this, it is easy to tell.

  5. cranky_EE says:

    Joe: I like your style.

  6. Alex H says:

    “This technique has you placing the object at an imagined 30-degree angle”

    Actually you rotate it first around the vertical axis by 45 degrees, then about the horizontal axis by ~35.2 degrees.

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