Linking AutoCAD DWG files - Revit Tutorial

- Design data comes in all sorts of formats, and you will frequently get files other than Revit. Some of the most popular formats are AutoCAD files or SketchUp files. And if you get files in these formats, you can bring those right into your Revit project and use them right alongside of the Revit geometry. So in this video, I'd like to show you how to bring in a CAD file, and I'll demonstrate the process using an AutoCAD file, but it supports many other file formats as well, and the process would be similar. Now, the best practice way to bring in a CAD file is to link it. And this means that it will maintain a connection back to the original file, so that if the author of that file makes a change and saves it, you'll be able simply reload those changes and bring the changes very quickly and efficiently back into Revit. So let's go ahead and get started. I've got an empty file here for this purpose, and we're going to go to the insert tab, and we're going to jump right to the link CAD button. All right, so I've got a couple CAD files here. If you click on the files of type dropdown, you will see that there are a number of file formats supported. So start off by choosing the file format that you want, and then select the file. I recommend selecting the file, not double-clicking it. If you double-click it, you miss the opportunity to change any of the options down below. Now, in this case, I've already got the options set the way that I want, but I'm going to point out to you what some of the options are, so that if you need to change some of your settings, you can. As you can see from the preview, CAD files are typically on a black background with a lot of bright primary colors. If you want to preserve those colors in Revit, you can. There's an option for that right here, but there's also an option to invert them, and another option to force everything to black and white. I'm going to choose invert here, because I want to see the file in color, so that I can easily tell where the CAD file is, but I'm going to choose invert, because the colors will be less bright and primary, and they will look a little bit nicer on the white background. Okay, so that's the main reason I'm choosing that. For positioning, I'm accepting the default of origin to origin. That's a pretty common best practice. It's not required, but it's a pretty frequent thing to do. So I'm going to try that. Now, CAD files are organized into layers. I'm going to accept all of the layers. I'm not going to worry about the units. Revit does a really good job of figuring out the units that are being used there. And so, it's going to auto detect those. And I don't need to worry about this correct lines that are off access. I'm just going to accept that. Now, over here, I've got a check box called current view only, and I can either check it or uncheck it. I'm going to leave it checked here, because I want to force this CAD file to display only in the view that I'm bringing it in, the level-one view, okay? So I'll show you how that looks in just a moment or two. All right? The alternative is to uncheck that, and then it will show in any view that would reasonably display it. So you would see it in planned views and in 3D views, for example. And it would be as if somebody had painted the lines directly on the floor versus what we're going to see, where it's only going to be part of level one floor plan. Let me show you what I mean. Let's go ahead and click open here and bring that file in. So starting with that notion of current view only, here in level one floor plan, this floor plan is associated to level one, but if I select the site plan, notice that it is also associated to level one. If I double-click the site plan, notice that the CAD file does not display here. Okay? Now, here in the site file, there are these symbols in the middle of the screen. This is Revit's origin, zero, zero, zero. I'm going to go back to the level one floor plan. And that's right about in this location. Now, if you come down here to the bottom of the screen, there's this reveal hidden elements icon here, and what this does is exactly what it says. It's going to reveal anything that's hidden in this view, which includes those origin symbols that I just showed you in the site plan. So as you can see, those symbols line up perfectly with the lower left-hand corner of the CAD file. So that's the second thing we did. We said, let's do origin to origin, right? So I'm going to turn off the reveal hidden elements mode. All right, the next thing I want to show you is a peculiarity when you use origin to origin. The file will come in pinned, if you do that with a CAD file. Now, I'm going to move my mouse over here and highlight, and then select it. If you're not able to do that, it's because this file comes in pinned. So if you come over here beneath the modify tool, there's a dropdown menu. There's a select links option and a select pinned elements option. You need both of those enabled in order to be able to select this file. If you uncheck either one, you will not be able to select it. So I uncheck pin. Can't select it. I'll put pin back on and uncheck links. Can't select it. It's only when I have both checked that I can select it. And then of course, that would allow you to unpin it. So what's the purpose of pin? Well, when something is pinned, you can't move it, rotate it, delete it. So it's a fail safe to prevent you from accidentally doing something to the file that you didn't want to do. So notice it's going to warn me, can't move a pinned element. So I'm going to cancel that. So should you need to move it, or rotate it, or delete it, you just simply unpin it first. Now, I'm going to undo that. All right, so I've got this CAD file in here, and now we understand the settings that we use to bring it in. Now, what? What can we do with this file? Well, let me zoom in a little bit here. And sadly, there's no way to just kind of push a button and have this two-dimensional set of lines and arcs that make up this CAD file turn into Revit geometry. This is just a static floor plan, but we can easily trace over it. And it's really not that difficult to do. So let me show you a quick example of that. I'm going to go to architecture, click my wall tool. I'm going to open up the type selector list here, and I'll choose an appropriate size for the exterior wall. Maybe a generic 12-inch. Now, move your mouse near the center line of the wall in the CAD file. And notice that Revit will sense where that center line is. So that's going to be really handy, because now I can use that as a tool to help me quickly trace over this. So I'm going to draw those two walls, press escape. I'll change the size to something thinner, like generic five inch. Now, these, in my experience, I find it's better if you don't try to snap them at the intersections. So what do I mean by that? I'm going to press escape, and I'm just going to try and find the center lines of these walls and just draw little short segments of them, okay? So notice, I'm not drawing the full wall. I'm just finding the center lines and drawing partial walls. Why? Because it's much faster for me to do it that way, then go to modify, come over here and start using the trim and extend tools to clean things up. So I'm going to use trim and extend multiple elements. I'll pick this wall as my boundary edge, and then I can extend this one and this one. I'll click an empty white space to reset that boundary edge. I'll pick this new boundary edge, pick this one, and this one. Reset, pick this new boundary edge, this one, and this one. Reset, this boundary edge, and this one. Reset. Now, I'm going to switch to trim and extend to a corner, and I'll take these two and finish it off. So you could see that even though it feels like it's extra work, it's really not that bad. And I think you get a much better chance of getting precision that way. At least that's the way that I usually do it in my experience. You're welcome to try other techniques if you like. Now, just to kind of make this look a little bit more like a Revit model, I'm going to throw in a couple doors here. Now, it looks like the door that I'm choosing is slightly larger than the one in the CAD file. I'm not going to worry about that too much for this demonstration, but you are welcome to choose a different size if you want to. But we're what I really want you to see is, after I throw a few of those doors in here, is that you want to draw your walls all the way across the linework in the CAD file. Don't stop and start at each of the openings, because remember, Revit's going to cut the holes for you, okay? So, now that I've done all of that, now what? Let's say that the author of the CAD file has made some changes. And we said we could reload those changes. So let's see what that looks like. Well, I'm going to go back to insert now, and this time I'm going to click manage links. Now, across the top of this dialogue, you'll have several tabs for all the different file formats that Revit supports. And there are lots of them. Let's stay focused on CAD here. So I'm going to click the CAD formats. Then I'm going to select my CAD file. When it highlights all the way across, you'll see a bunch of buttons down at the bottom. If the original author of the file has made a change and saved it in place over the original, you can simply reload. If they sent you a new file with a new name or saved it in a different location, you can instead choose reload from, point to that new file. So I've got an updated version here, click open, click okay, and now, you'll see that new file will update in place. Now, once again, Revit's not going to immediately recognize the change because the CAD file is just linework, but it's easy enough for you to select the elements that have been affected by the change and move them over, snapping to the linework underneath. And that's how you could do this sort of hybrid approach between a CAD underlay and the Revit model on top. And just to remind you once again, this is current view only, which means that if I switch to another view, like the default 3D view, hold my shift key down and spin it around, I don't have to worry about the CAD file showing through here. All I'm going to see is the Revit geometry.