House plans - one well known drawing format, are a form of orthographic projection.

1. Cape Style House 3 Lobed Monolithic Dome House Orthographic Projections • Graphic communications has many forms. Orthographics is one such form. It was developed as a way of communicating information about physical objects. It is part of a universal system of drawings.  House plans - one well known drawing format, are a form of orthographic projection. 

2. Simply Put • Orthographic drawings are views (front, side, top, and so on) of an object. • It is a way of representing 3-dimentional shapes using several views in 2-dimensions • An orthographic view is only one side of a drawing

3. It takes several views to show all the object Before getting to views, it is useful to look at another type of drawing. • Pictorial drawings show several sides at the same time. • Many people find these drawings easier to understand.

4. Isometric Drawings The most common pictorial drawing • Isometric drawings were developed to approximate perspective, but are much easier to draw. Isometric View – When two of the three perspectives or axis are exactly 30 degrees to the horizontal

5. Labeling a Pictorial Drawing • A simple box has 6 sides - top, bottom, 2 ends and 2 sides. An isometric drawing of a box looks like this.

6. Add labels to the sides... • These labels are OK, but in the world of technical drawings, special labels are used. • The label refers to a position on the drawing. Rear View Left Side View Top View Front View Right Side View Bottom View

7. One important thing to note is that these labels are for the position of the object. Front view is always in this location, regardless of the object that is drawn. In this drawing, Front View is actually of the side of the truck, Right Side View is of the front of the truck, and so on…. You may well ask, "Why not draw the truck so that the front of the truck corresponds with the Front View, and so on?". The answer is related to how this kind of drawing is used to develop orthographic views.  By placing the longest part of the object in the Front View, we need less space to draw orthographic views (projections).

8. Makings An Orthographic Projection • There are several ways to illustrate how isometric drawings relate to orthographic views.  Start with an isometric box Think of it as a real box.  Imagine cutting the box along the corners so that it lays flat.

9. If you make a particular set of cuts, the box will unfold to look like this As you can see, the six sides unfold in a pattern. Notice the central location of the Front View

10. Do we really need all those views? • Three sides are normally used to make orthographic projections - Front View, Top View and Right Side View. This image has the rear, left side and bottom views removed.

11. So far • We have taken an imaginary box • Cut it along several edges, folded it flat • Cut off 3 of the sides.  • What we are left with is 3 sides of the box.  • The next step is to separate the remaining sides. The Front View, Top View and Right Side View are still in the same relative position to each other. 

12. In the pictorial drawing, we are looking at a 3 dimensional object, and all the surfaces are tilted away. Orthographic projections are several orthographic views describing a 3 dimensional object They are always located in the same relative position to each other

13. Isometric Pictorial View Orthographic Projection

14. The Glass Box Method Visualize a glass box surrounding the object, then mentally unfold the box.

15. How Isometric Pictorial Views and Orthographic Projections “Match” Up Isometric Pictorial View Top View Orthographic Projection Top View Front View Right Side View Front View Right Side View

16. Isometric Pictorial View Orthographic Projection Top View Right Side View Front View

17. Matching Example Isometric Pictorial View Orthographic Projection Top View Top View Front View Right Side View Front View Right Side View