Setting drawing units - AutoCAD Tutorial

- We're starting a new chapter now in this course, and what we're going to be looking at is units and options in AutoCAD. We've got a new drawing for you. It's called surprise surprise units&options.dwg. You can see the name of it there at the top of the screen and you can download it from the library to follow along with the videos in this particular chapter. When you do open up the file though, make sure that you are on layer zero, which is right at the top of the layer dropdown, just there, just click on the zero that makes it the current drafting layer. Also make sure that you are in the model tab here, bottom left of the screen so that you can see your floor plan. Now we're going to start moving through how we utilize units and the options dialog box in AutoCAD. So with our floor plan, let's have a look now at how our units are set up in AutoCAD. Now one of the things that is a giveaway for units is dimension. So you'll notice we've got lots of red dimensions on this particular drawing. And you can see they're in their thousands and even tens of thousands. That's because this drawing is drawn in millimeters. Normally when you're working in AutoCAD you work full size in the model tab. So I've got a floor plan here that has been drawn full size as if I'd gone out and measured the floor plan in millimeters. And that's how we work here in the UK where I'm based. An architectural floor plan would normally be drawn up in millimeters. So for example that dimension there ten three six three that's roughly 10.4 meters because it's 10,363 millimeters. Now normally in context, if you want to check your units in an AutoCAD drawing, you would zoom into a known quantity such as a doorway, and we've got plenty of those. I'm going to zoom in on this doorway here. I'm just going to get in nice and close rolling up on the wheel. And a little trick you can use is to measure a doorway. So in the home tab on the ribbon, if you go to utilities here and click on measure and just go to distance, making sure your object snaps are on down here, there they are. Object snaps are on. I can snap from this end point snap left-click and go to this end point snap here, left-click. And that doorway is 1155.7 millimeters wide. Now obviously you wouldn't worry about 0.7 of a millimeter. The reason being is this drawing possibly has been converted from an imperial drawing at some point and scaled up into millimeters. But the distance there in context is 1.155 meters or 1,155 millimeters. It wouldn't be for example 1,155 feet or 1,155 inches. So that's how you can measure something in context and get an idea of those units. So let's just hit escape a couple of times to close out the measure command there. And I'll double click on the wheel just to zoom to the extent of the visible drawn objects again. Now that's how to gauge your units in context of your drawing. What about how your units are displayed on the drawing? How does that work? So for example when we did that measure of that doorway, you could see that a length had two decimal places that 0.70 millimeters. So we just type the word units. It's that simple. There's the units command there, it comes up on my dynamic input like so along with the suggestion menu. Just type units, press enter. That'll bring up the drawing units style of box. Now bear in mind this is not how you set your units. If you're going to draw something in the model space you'd draw it and just draw it as unit. So my units are millimeters and I know that because I'm working in millimeters. There's no button in AutoCAD to say, oh you're working in millimeters. All this drawing units dialog box does is it displays the units you're working in. Now for example, if I'm working in millimeters, that's a decimal length, isn't it there. So there's my type decimal. Now if I wanted to work in imperial and display feet and inches, I would use something like architectural. As you can see there's a precision there, basically the precision there is every quarter of an inch. But I'm going to go back to decimal because I'm in millimeters as you can notice. I don't want to be in feet and inches but if I did, I'd use a different drawing unit setting. Also you've got there engineering, as you can see inches. And we've got fractional which is also inches but without all the little sort of speech marks and apostrophes that represent the imperial measurement. Now also as well, you could potentially be working in decimal inches. You might be drawing 1.5 inches, 1.5 feet. So this is representative of the display of your unit only. That's all it does. It displays what you're working in. So just be aware of that. AutoCAD is not going to say, oh are you working in millimeters today? You have to decide that. You have to decide how these units are going to be displayed in your drawing units dialogue box. So for me, it's millimeters metric decimal like so. And you can see the precision there is two decimal places. That's why we got that 0.70 showing up when we measured that doorway earlier. So what I'm going to do here, is maybe set that to one decimal place. Just so I know if there's any weird discrepancies of say half a millimeter here and there, it means I can update things and change settings and even change geometry if I need to. Now, decimal degrees. You've also got things like degrees, minutes and seconds. You've also got gradients and radians which involve Pi when you're working with circles and so on and 360 degrees. And if you're working in surveys units you might be working to points to the compass. You can see North and East there in the precision. Again, I'm just going with good old decimal degrees which tends to be the default setting. Now you'll notice my precision there is quite high. And the reason for that is, over long distances a small discrepancy in an angle can get bigger and bigger like the slice of a pie. So it's up to you what precision you use. Normally I double what I'm using for lent. So in this case I could potentially go down to two decimal places. You'll notice as well clockwise here I've got that unticked. AutoCAD by default measures angles anti-clockwise. And that's always been the norm. As long as I've used AutoCAD I've always measured angles in AutoCAD counter-clockwise or anticlockwise. If you want to use clockwise, tick the box. Insertion scale. We will cover this a little bit in this chapter, but ideally because I'm working in millimeters the units to scale in certain content would be millimeters. Now ideally anything I want coming into this drawing whether it be a block or I've blocked another drawing to bring into this particular drawing I want it to come in in millimeters. Now we'll cover insertion units and things in one of the videos in this chapter. So don't worry too much about that right now. But my drawings in millimeters. So the units to scale certain content should be millimeters as well. Sample output shows you what you're going to get on the screen there. Lighting. You don't need to worry about. That's when you're setting up lighting in 3D models. Direction here though, we do need to worry about that because this applies to our clockwise anticlockwise setting here. So East at the moment, going to the right is zero degrees. As we go counter-clockwise, North would be 90 degrees, West 180 and so on. If you need to change that direction control, sometimes you do because of project constraints, company standards, et cetera. The default though, which we will be using will be East set to zero and we are okay. All I've got to do now is click on okay, and my units are all set up in my drawing.