Linking AutoCAD DWG files - Revit Tutorial

- [Tutor] In this video, I want to show you how to link a CAD file into your Revit project. So many folks will be working on project teams where they will have to access data that's been created in other programs and the most popular program is AutoCAD and it's DWG file format. With Revit we can link in files that have been created in those other file formats. So to do that, we're going to go to the insert tab and there's a link CAD button right here. Now, when I choose link CAD I can browse to a folder that contains drawing files and I'm going to select this file right here called AutoCAD floorplan. Now you'll see the preview for it appear over here. Now, there are different file types supported by this link functionality. So we're using a DWG but you could also choose DXF or DGN or even SketchUp files. So in this case, I'll leave it set to DWG. Now, beneath that there's several other settings that we want to walk through here. So, the first is how you want to treat the colors in the file. As you can see here in the preview, it's on a black background with these bright primary colors. And if you preserve those colors it's sometimes difficult to see on a white background. So since Revit's on a white background I think invert is usually a nicer choice if you're going to preserve the color. Optionally, you could also remove the color and force everything to black and white. That's usually a pretty good idea if you're going to print out that CAD file along with your Revit project. CAD files are organized usually in something called layers. So if you want access to all of the information in the CAD file, choose all of the layers, but there is an option where you can specify individual layers and so if you know for sure that you only need certain layers you can choose that option. In this case, I'll choose all. Units can be any number of things, but usually the autodetect feature which is set by default will do a good job at figuring out what the units are in the imported file. So, I recommend you do autodetect unless there's a problem and then you can undo and then try again with a specific unit. Now in some files, lines can get slightly off axis as Revit calls it and this means that down to multiple decimal places they might be slightly off in angle and so forth. So Revit has the ability to correct that for you and for simple line drawings, like a floor plan or something, that's usually a pretty good choice. If you have a file that's like a large site plan or something that's very organic geometry or just really large in scale then choosing that option may not be the best choice because it might actually create more problems than it solves. So, you might have to experiment a little bit, but in the case of this simple floorplan lines that are off access is a pretty good idea. Now, as far as positioning goes, we have several choices, we can center the file, we can put it at the origin. A lot of folks will favor putting it at the origin, so that's what I'm going to choose here. But if it comes in in a strange location you can always move it later. Now, the final setting that I want to talk about is current view only. What this does is it interprets the information coming in from CAD and decides whether or not it should be view specific or treated like part of your model. If you check the box, it's going to treat it like view specific information, meaning that it would only show in the view that I placed it in, in this case, the level one floorplan. If you uncheck that, it will treat it like model information even though it's actually 2D data. So, what you'd have is a bunch of lines that are drawn on the floor but you'd be able to see them in plans or in 3D views. So they would show in multiple views. Now, in my case I'm intending to bring this file in and just use it to represent the first floor for tracing purposes and I don't want it to show on the second floor or in 3D views. So I'm going to choose current view only. So let me go ahead and click open here and that'll bring in the file. Now, the Revit origin is right about here in the middle of the screen and the AutoCAD files origin is right about there in the lower left-hand corner. So you can see it just line those two points up. If you don't like where it came in, you can select the file and move it. Now at the moment, I can't move it because when I bring it in into origin origin, Revit automatically pins it. And when you pin something's positioned that just means prevent it from being moved. So if I wanted to move it, I could unpin it and then I'm free to move it wherever I like. Now, I'm going to undo that and I will select the file and repin it. If you're not able to select the file, there's two possible reasons for that. Under the modify tool here, there's a select dropdown and if you have either select links unchecked or select pinned elements unchecked, either one, you won't be able to select this file. So if I uncheck one of these, now I can no longer select this file no matter what I do. So just make sure that both of those check boxes are checked. If you want to be able to click on and select this file. Now, it doesn't really matter where you put it in this case, so I'm just going to leave it right where it is, I'm not going to move it and I'll go ahead and zoom in. So what can we do with a CAD file? Well, one of the things you might want to do is actually trace over it with Revit geometry. Remember, this is just the 2D CAD file that we've brought in, it's not actually data of Revit geometry, so Revit really can't do anything with this information. But if I go to architecture and click wall and I'll choose a wall type, let's do a generic 12 inch wall. You're able to snap to any of the geometry in this CAD file. So if I kind of move around I can find intersections and it will find nearest points and midpoints and even end points. So you'll be able to locate different points in that file. But another really interesting thing occurs too, if you put your mouse between two parallel lines in this file, it will figure out where the center line is between those two parallel lines. And what that allows me to do is trace over this CAD file with a great deal of accuracy by placing these centered walls right down the middle of those parallel lines. Now I'm going to press Escape one time and change my wall type to something thinner for the interior, so generic five. Let me zoom in a little bit here and for these walls I want you to just kind of place them roughly. So I'm not going to try and match up exactly. In other words, I'm just going to draw down the center, press Escape, draw down the center, press Escape, draw down the center and press Escape. And the reason for that is I want to show you the trim and extend to a boundary command to clean this up. So you can see how I've sort of left all those walls with gaps at the end. Now, you can see why I chose to bring the CAD file in in color now, because as you're tracing over it with your Revit geometry it starts to cover up the colors. And so as the colors slowly disappear then I kind of know where I've been and what I still need to trace. But let's go ahead and clean up some of this right here and I'm going to use the trim and extend to a boundary command for that purpose. So I'm going to go to modify and there's two versions of that command, I'm going to choose this one that allows me to do multiple elements at the same time. So, the first thing you need to do is pick a boundary element. So I'll pick this exterior wall that we just drew. Then it wants you to pick the element that you either want to trim or extend. Now, I don't have anything to trim but I do have some things to extend this wall and this wall. And because this command is multiple elements you're able to extend as many elements as you want until you're satisfied. If you want to reset the boundary just click anywhere in empty white space and that clears the selection of everything and then I can choose a new boundary and I'll pick that wall right there. And now, instead of picking them individually, what it can do is actually click and drag through multiple elements right there and extend them all at the same time. Now the boundary is still active, so if I pick another wall, it will extend to that boundary until I click an empty white space to reset. So now I'll pick another boundary here, drag through these objects here and then again, the boundary is still active. So now it matters what side I click because I want to trim an element instead of extending it. So if I click on this side, it would keep the top half and this side, it would keep the bottom half. So once I've done that I can add some doors in here. So I'll go to doors, I'll choose an appropriate size and place some of these doors and kind of snap them to the locations of the existing doors in this CAD file and it will cut the holes and make the modifications of course. Now, I could keep going, of course, there's lots more to draw here but what I want to do is take you into a 3D view and show you what we've got. So I'm going to click the default 3D view icon and I'm going to hold down my shift key and orbit the view by dragging the wheel on my mouse and then I'll zoom in. And you can see that all of the Revit geometry is showing here in this view but the CAD file is not. So recall that when I brought the CAD file in, we checked the box to say current view only and that's why it's not appearing here. Now let's say that we are continuing to work but then we get notice from the original author of this drawing saying that they've made a change and that we might want to update. Well, this is exactly why we chose link because by linking it in, it makes it very easy for us to update the file if changes occur. So the way that you do that is to go to the insert tab and choose the manage links command. So when I click that, that will display a manage links dialogue and there are several tabs here and I'm going to go to the CAD formats tab and there is my AutoCAD floorplan. Now, if they sent me the file with the same name and it just overwrote the original, I could just simply click the reload button here. Now, in this case, it'll reload but it's reloading the same file. So what I'm going to do instead is, they sent me a file with a different name, let's say, I'm going to choose reload from and then I've got an updated version of it right here. I'll open that and I'll click okay And now you'll notice that the CAD geometry underneath has changed but the Revit geometry on top does not change. So, the Revit geometry is not linked to the CAD geometry in any way but now that we see that a change has taken place, we could select our Revit geometry and then I'm going to use my move command, let me turn off disjoined here and then we could move it into position relative to the new location of the CAD geometry. So using CAD files in Revit is a pretty easy thing to do, you just link it in and linking is preferable in most cases because as we saw here, we're able to update that link and therefore we can collaborate back and forth with a team that's using both Revit and AutoCAD for different aspects of the same project.