Join Jeff Bartels for an in-depth discussion in this video Converting units from Imperial to Metric, part of AutoCAD 2014 Essentials: 02 Drawing Fundamentals.
Before we jump in and start working on tutorials, I wanted to take a second and talk about how AutoCAD handles units of measurement. You see AutoCAD is used by many different industries. Like architecture, civil and mechanical engineering. Surveying and product design for example. Now each industry has their own standard unit of measure for the drawings they create. Some use imperial measures like inches or feet, metric units like millimeters or centimeters are also popular choices. It's important to note that the majority of the tutorials used in this title were created using imperial measurements.
On occasion, I've been asked if it's possible to convert the Exercise Files in this title to metric units. Such that this course could be taken from a more metric perspective. Let me say that it is possible to convert the drawings to metric. However, it will require more work than you might first expect. Let me show you what I mean. As you can see I've just launched AutoCAD, and I'm working in the empty default drawing file. I'm going to create a rectangle. I'll do that by moving up to the draw panel, and I'll launch the rectangle command.
I will then pick a point on screen to start the rectangle. I'll select dimensions from the command line, and I'd like this rectangle to have a length of six. I'll press Enter, and we'll give it a width of two. I'll press Enter than I'll click on the screen to finish the shape. Let's zoom in. We'll center the geometry on screen. I'd also like to add some dimensions to make it easy to remember the size of this geometry. I'll do that in the annotation panel, I'll launch the linear dimension tool. I will then press my Space bar and I'll select this uppermost line and I'll pull out a dimension.
I will then tap the spacebar twice to relaunch the command. I'll select this vertical line on the right side, and I'll pull out another dimension. So we have a rectangle that measures six by two. My question is, what does this measurement of six represent? Is this six inches, six feet, or is it six millimeters? To find out we're going to take a look at the units assigned to this drawing. Let's zoom out slightly and I'll pan the geometry over and then I'm going to open the Application menu, I'll come down to Drawing Utilities and I'll select Units.
Right here in the middle of the dialogue box is where we declare the unit of measure for this drawing. So in this case, the rectangle that we see on screen measures six inches by two inches. Now let's say this drawing represents one of the Exercise Files and I would prefer to do the tutorial using metric units. I'd like to work in centimeters for instance. In the drawing units dialogue box, I will open the Units menu and select centimeters and then I'll come down and click OK. And notice the rectangle doesn't change it's still six by two.
You see AutoCAD really only sees units, this rectangle is still six units long except now we've declared that those units represents centimeters. So to convert an exercise file to metric, the geometry in the drawing will also need to be scaled up or down to compensate for the change in units. Let's look at how we can do that. I'm going to start by setting the units back to their original setting in this drawing. Let's open the Application menu, I'll come back to Drawing Utilities and I'll choose Units. Let's change this back to inches, and I'll click OK.
Then I'll move up to the Quick Access toolbar. I'll launch the Save As command. And, let's save this drawing out on the desktop. I'll call it six by two rectangle inches. And I'll click Save. Then I'll click the X in the upper right corner of ModelSpace to close the drawing. At this point the drawing we just saved represents a Standard Exercise file. To convert the units of the file, I'm going to create a new drawing. I'll do that by clicking the New Drawing icon.
And in the Select Template dialogue box, I'll choose acad iso. This template represents an empty drawing that is preconfigured for metric use. I will then select Open. Then we'll assign the appropriate units for this drawing. We'll go back to the units dialogue box. And remember I wanted to work in centimeters. So I'll open the menu and switch this to centimeters and I'll click okay. Finally I will insert the exercise file into this drawing and AutoCAD will automatically scale the geometry for me.
I'll do that by visiting the Insert tab on the ribbon. I'll click the Insert button. Then I'll choose Browse. And out here on my desktop, I'll select the drawing that we just saved. I'll click Open. And in the insert dialogue box I will make sure that each of these selections is unchecked. The only one that I'd like selected is Explode. This way the geometry that is inserted, will be inserted as individual entities, and not as a symbol or a block. When finished, I'll click OK. Then I'll double-click the mouse wheel to a zoom extense, so we can see the rectangle.
I'm going to zoom out just a bit. And as you can see, the dimensions have updated to accurately reflect the size of this geometry in centimeters. So, the file has been successfully converted. That being said, there are a few more things we need to consider. When you scale an exercise file this way, the size of the annotations may also change significantly. And they may need to be resized to make them legible. Likewise, the dimension style used in the drawing can have its own independent units setting.
So in some cases, the dimension style may also need to be modified such that the measurements read correctly. Another thing to consider, if any special line types were used. Like hidden or dashed lines. These may need to be rescaled to ensure they look proportional with the resized geometry. If the converted drawing includes premade layouts for plotting, those will probably need to be converted or recreated due to the change in the size of the geometry. Finally, and probably most important, if you rescale an exercise file to use alternate units and then work through the video tutorial, you'll need to convert each of the dimensions that I give you to coincide with the units you've chosen to use.
For instance, if I'm working in a drawing set to inches, and I ask you to move an object a distance of six, that six represents six inches. If you have scaled your exercise file to use centimeters, you'll need to manually convert the measurements I give you to centimeters. In the case I just mentioned, a distance of six in your drawing would need to be entered as 15.24, because each inch represents 2.54 centimeters. In my opinion, even if you have a desire to work in metric, I would strongly working through the tutorials in this title as they were created.
Using the imperial measurements. In the big scheme of things, it won't affect your ability to learn or understand the material. In fact, the workflows will be identical. The only difference is that the numeric measurements you enter will represent feet or inches, rather than your desired metric equivalent. After working through the exercises in this title all new drawings that you work on can easily be created and edited using the units of your choice.
- Constructing lines
- Defining a unit of measure
- Locking to geometry with object snaps
- Drawing rectangles, circles, and polygons
- Applying hatch patterns
- Moving, copying, and rotating objects
- Erasing elements
- Undoing and redoing actions