In this video, Shaun Bryant demonstrates how to create a simple 2D subtracted region, which is then extruded into a 3D solid.
- [Instructor] Welcome to another AutoCAD Tip & Trick for today. Now what we're going to look at is working with a simple Region in AutoCAD. And this is like a little bit of an introduction into some 3-D drafting if you've never used it before. Now we've got to new drawing for you. It's SimpleRegion .dwg. You can see the name of it at the top of the screen, and as usual, you can download this from the website to follow along with this particular AutoCAD Tip & Trick video.
Now what we've got is a little gearwheel, and the gearwheel at the moment is made up of lines and arcs and circles, and all of those elements are just separate AutoCAD entities right now. Now what we're going to do is we're going to convert all of these entities into Regions, and we're going to create two separate Regions in this particular case. Now, the quickest way to do this is just to do a quick crossing selection first, but before we do that, where is the Region command? It's very easy to find.
Home tab on the ribbon, Draw panel, if you click on the fly out, it's that icon there. So just hit the pin, to pin out the fly out like that, and it will stay open, and I'm going to click on Region. And that converts an object that encloses an area into a region object. So I'm going to click there, and I'm going to select the inner circle, like so. That basically represents the hole where the shaft would go through this particular gearwheel. So if I click there on that circle, and then just press Enter to finish, that now creates a Region.
You can see there, "1 loop extracted, 1 Region created." So if I hover over that now, it's now a Region in the similar way that you could create polylines, for example. Now, because it's a Region, I've created a separate Region layer. So what you might want to do is select that now, go up to your Layer drop-down here, and just make sure that it's on the Region layer, which is red. Hit Escape to deselect. It's pretty obvious that red is Region, and anything white is just an AutoCAD object on the Objects layer.
Now we need to convert that other, sort of, what I call circle, teeth, circle of teeth, whatever you want to call it, it's a gearwheel, and obviously it's got the teeth on it that go round it in a circular fashion. Now, I would just do a crossing selection, so click once here, bottom right, and just drag your crossing selection over everything, and then hold down Shift, and just click on the Region to deselect it, 'cause it's already a Region. We then go back to the Region command here, click on it, and it says, "Select objects." Hang on a minute, why is that? Region is one of the only commands in AutoCAD where you have to go back and select the objects.
It doesn't do that noun verb selection thing, so you do have to click on Region first. So then I can click again, crossing selection, like we did earlier, and then hold down Shift, just to deselect the Region that we've already corrected in the middle of the circle. Press Enter to confirm, and you'll see again, down on the command line, "1 loop extracted. "1 Region created." So that is now a Region as well, so if I hover over it, it's made all those lines and arcs into one Region. So I'll select it, and again, just pop that onto the Region layer.
It's always good to have your Regions on a separate layer to the rest of your AutoCAD objects. Just hit Escape to deselect, like so. Now, I'm going to unpin the Draw panel, that's done, that'll go flying back into the ribbon, and now what I'm going to do is utilize my ViewCube, over here, so you'll see that I can click on a corner, and that'll take me to an isometric view, or what I can do is use my views up here, in the View controls, and I can pick an isometric view there as well. Now the one I'm going to look for is SW Isometric, like so.
So I click there like that, and that would've taken me to this corner on the ViewCube. So you can use either. And I'm just going to roll back on the wheel just a couple of notches so that we can see what we're doing, and pan the little gearwheel regions down a bit. Now what we're going to do is we're going to subtract one Region from another. Now you can go to your 3-D modeling workspace and the Subtract command is on the ribbon, but all we've got to do is type the word subtract, so. Just type in subtract like that, and you see, there's the command there on the suggestion menu, I press Enter to confirm.
Now read your command line. It says, "Select solids, surfaces, and regions "to subtract from." So I'm subtracting from this one. I select it, I then press Enter to confirm that selection. Then it says, "Select solids, surfaces, and regions to subtract." I select the inner circle, here, 'cause that's going to be the hole in my Region where the shaft goes through for the gearwheel, and I press Enter again. Now it doesn't look any different, but if I hover over it, can you see? It's now all one Region with a hole in the middle, 'cause I've subtracted that hole from the gearwheel.
Now, we're in an isometric view, which is great, I can now see what I'm going to do in 3-D. Make sure, though, that your current layer now is Region. 'Cause when you use the EXTRUDE command, it extrudes onto the current drafting layer. So, again just type extrude, E-X-T-R-U-D-E, just so you know. Don't worry about MESHEXTRUDE that comes up on the suggestion menu. Just use EXTRUDE, press Enter.
Select the object to extrude, we select our Region with a hole in it, like so, and we press Enter to confirm. Soon as we do that, and start moving the mouse, can you see? We're actually giving this a thickness. So we're making it into a 3-D solid. So just drag upwards, vertically, with the mouse, and you'll see the little distance there on the direct entry box. Type in 100, and press Enter. You've now got a 3-D solid. You've now made a 3-D gearwheel out of your little Region with a hole in it.
It looks a bit weird, though. That's because the visual style over here, top left, is set to 2D Wireframe. Change that to something like Conceptual, and now you can see what you've just created. If you hold down Shift on the keyboard, and hold down the wheel on your mouse, and then move the mouse, you can do what is called a 3-D orbit, and as you orbit down, can you look, see, there's our hole in our gearwheel. How lovely is that? So we've just created a very basic 3-D solid. If you release the Shift key and release the mouse wheel, obviously it just goes back to your regular zoom in, zoom out kind of settings like that on the mouse.
Now the good thing is, because it's a 3-D solid, I can now use the ViewCube and my views here, I can look at the Top view, like so, I can look at a side view, let's go for the Left view, for example, and I can see all the gears, can you see, in vertical fashion like so. Or if I go back to the ViewCube here, I can go to a different isometric view, I can change it back to Top, like that. I can rotate the ViewCube, so I can rotate the views as well. And what you always want to work with here, by the way, is your WCS, your world coordinate system.
And you'll see now that that's the Left view, can you see? So what it's done is it's always reverting to the Top view. So if I click on that arrow, there's my Top view again, I can go back to an isometric view, like that, and so on and so forth. But what you've done there, from a very simple 2-D drawing, is generated a 3-D solid. And that's how you can work with your simple regions and then extrude them to generate reasonably complex 3-D solids.
Skill Level Intermediate
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