First angle and third angle projection - SOLIDWORKS Tutorial

- [David] Before we move forward, I highly suggest going back and taking the SOLIDWORKS: Drawings course available here on LinkedIn Learning. This is the introductory course for creating SOLIDWORKS drawings and will give you a good base to start from when approaching the content in the following videos. If you have completed this course, let us now discuss orthographic projection. When working with vendors domestically and internationally, it becomes even more critical to understand orthographic projection. In all of the examples that we're going to review in this course, I'll be using third angle projection. That is the standard used here domestically in the United States. If you're an international student watching this course, you may be using first angle projection. This is the standard out of Europe and other areas of the world. If you've ever looked at a 2D drawing, you may have noticed inside of the title block somewhere, you'll see the symbols to signify if you're using first angle or third angle projection. These images are seen right here in the top right corner. We can see on the top first angle projection in the symbols on the right, as well as third angle projection in the symbols on the right. Now, you'll notice that they're essentially the same symbols but they swap their position and I'll explain why in a moment. Here below you'll see a definition that's available on Wikipedia or inside of any textbook showing where these two projections are driven from but I want to break it down to a much easier example. I like to focus on the example of an object on or inside a bowl. If we look at first angle projection, think about it like this. Put yourself in your kitchen. Grab a bowl. If you place that bowl upside down on top of your countertop so that the open part of the bowl is facing down, you're standing over it and you look down straight on at the bottom of the bowl, if you put an object on that bowl, you'd be looking at the front view. If you slide that object down to the right of the bowl, still looking straight on at the base, you will now be revealing to yourself the right view of that object. So again, imagine an upside down bowl, place an object on it and if you slide it down to the right while looking straight on from above, you will see the right view of that object and that is how first angle orthographic projection works. Another way to visualize this is by placing that item inside of a clear box, a glass box. Orthographic projection at its core is simply tracing while looking at something straight on. We are projecting what we see normally or orthographically straight on onto some plane. So if we look here in these images, imagine, like shown here, that we take whatever this object looks like, looking straight on to each window and trace the lines that we see. If we then take that glass box and open it up and lay it down flat, we reveal to ourselves the six views that are available using first angle projection. Always by default in the middle we have the front view. To the right of that, we have our right view. Right one more time is the back view. To the left is our left view. Down below, the bottom view, and up above, the top view. So again, that's front, right, back, bottom, left, and top. And based on using first angle projection, we see these views in a certain orientation. Now let's take a look at the definition for third angle orthographic projection. Again, I'd like to use an example of an object inside of a bowl. Imagine placing a bowl on a flat surface with the open side facing directly up. You now place your object inside of the bowl. This will give you your front view if you're looking directly down at it from above. If you now take this object and slide it up the right edge, as it rotates around the walls of the bowl, this will slowly reveal the right view. Looking at it in another way, you can imagine again that our object is inside of a glass cube. If we trace the exterior faces with the lines that we see, just trace what we see, project it out again onto those clear walls, we can then open it up, this time starting from the front and lay it down flat and this gives us our six drawing views. Here we see our front view, our right view and our back view, our bottom view and our left view. Here we see the top view as well. Compared to first angle projection, the left view and the right view have changed positions. And this is due to the fact that we're rotating our object differently. So we rotate our object 90 degrees in between each of these views but when you're using the third angle view or the first angle view, you rotate that direction 90 degrees oppositely for each scenario.