Join Paul F. Aubin for an in-depth discussion in this video Understanding CAD inserts, part of Revit 2018: Essential Training for Architecture (Imperial).
- [Narrator] In this video I want to look at another use for bringing in CAD files into your Revit project, and that is for typical standard details. So, many firms have libraries of standard details that they've accumulated over the years, and often, many of these might be created in AutoCAD or some other CAD program that predated your use of Revit. So you certainly could recreate all of those existing standard details directly in Revit and create them in native format, and that would be preferable ideally, but you might have a hard time justifying the time and effort that it would take to do that. So an alternative is to simply use the existing CAD library that you have and import those details into your Revit projects and print them right along with your Revit project sets.
And so that's certainly possible to do. So that's the process I'd like to look at here. So the first thing I want to do is decide where I want to put this imported detail. When I look at the project browser, you'll notice that I'm in a level one floor plan, and that's probably not the best place for importing details. So it turns out that Revit has a view type specifically for this purpose. On the view tab on the create panel, we'll click the drafting view button. This will display a drafting view dialogue where you can give it a name, and it will suggest a scale.
1 to 10 is the default. I'll go ahead and accept that, and this will create a blank sheet of paper that's not connected to the model in any way. So drafting views are perfect for bringing in imported details, or for drawing new standard details, or creating diagrams or sketches, anything that doesn't need to be connected to the live 3D model. So now that I have my drafting view, the next step is to go to the insert tab and bring in the CAD file. Now we certainly could do it with link CAD like we've done in the last few videos and some CAD and BIM managers would insist on that, so certainly check with your own CAD or BIM manager to find out what your office standard procedure is in your firm.
But just to give you an alternative, I'm going to use the import CAD in this example. So I'll choose import CAD, select this auto CAD detail file at the top, and then let's talk about the settings that we want to use down at the bottom. Because I'm going to bring this detail in and use it directly in my Revit project, this time I'm going to change the colors to black and white. So what that will do is it will remove all this color information that you see here in the preview and just force all those lines to black. I am going to bring in all of the layers, I'm going to auto detect the units, and for this detail, I will correct lines that are slightly off axis.
Now I do want it to be current view only, but it should do that automatically since we're bringing it into a drafting view, but just make sure that that's checked anyway. For positioning, the default of origin origin may not give me a desirable result in this case. I don't really know where the origin of this detail is. It might be off screen, I might have to go hunting around for it when I bring it in. If you use one of the manual options instead, in particular manual center, what it's going to do is put your cursor right there in the middle of the detail and make it much easier to place it where you want and to of course find it after it's been inserted. So let's choose manual center and I'll click open, and then you can see the detail is right on my cursor and I can just click anywhere to place it.
Now I'll do z + f to zoom to fit and you can see that we've got this CAD detail loaded in right here. Now I'm going to zoom in a little bit closer and the only problem is the detail is a little bit flat. There's no distinction in the line weights, everything just kind of feels a little bit lifeless. Now let me zoom back out again, and I'm just going to kind of pan over here and give myself some room. So what I want to do is change some of the settings and bring the detail in a second time. If you think about what we did, we removed all the color information and forced it all to black.
Well, a lot of legacy CAD details actually use the color information to determine what the line weights of the information is. So because we've removed all the color information and we've kind of ignored it, we lost that line information as well. But it turns out that you can actually read that color information into line weights through a mapping table as you're importing the file. To do that, look on the import panel here of the insert tab and notice that there's a small little dialogue launcher button over here on the right. I'm going to click that, and that will display the import line weights dialogue.
Now, on the left hand side of this dialogue, you have 255 numbers which correspond to the auto CAD colors and on the right hand side you have a collection of line weights that we are going to assign to those values. So what you could do is click into any one of these fields and use whatever line weight value you wanted to use. Well, to save us some time in doing that, I've already pre-built a line weight mapping table here and saved it as a text file, and we can just simply load that in. So if you click the load button here, go to your exercise files folder, and the file that I've created is called detail line weights.
So I'm going to go ahead and open that up. That's going to load in all the values, and if you start to scroll through the list here, you'll notice that some of the entries have changed. Color number 31 is different. Scroll a little further down and you'll see locations where we've got several line weight values assigned here. So we've gone through and found the colors that were actually being used in that auto CAD detail and then assigned them to the desired line weights on the Revit side of things. Now I should point out one other thing, there's a note here at the bottom that says that these mapping values will be used anytime the layer from auto CAD uses a default line weight.
So in other words, if you go into your auto CAD file and actually assign a line weight to a layer, Revit won't look at this table. It will just use that line weight value. If however you leave the line weight unassigned, leave it set to default, that's when it will look at this mapping value. So it really depends on how the CAD file was saved. This particular file, all the layers are set to default therefore this mapping table will kick in. So let me click okay, and what you'll see is nothing happened to the existing detail.
So in order to see the effect of that change, you have to reimport the CAD file. So I'll just click import CAD again, select the same detail, accept all the same options, and click open. And now I'll place it over here and I can delete this one. And when we zoom in over here on this one, you'll notice that it's now using line weights. So very important when you're bringing in CAD files, particularly if you plan to print them with your Revit document set, you want to consider this mapping table so that they come in in a more desirable fashion and graphically look a little bit more desirable in the final output.
Now I've also provided a reset file, so if you go back to import line weights and you click load, there's a reset file here so that'll set everything back to one just in case you don't want to keep those settings that we loaded in before. So anytime you want to bring in a standard CAD detail, one of your options is to just simply import that detail on a drafting view and use it as is. This is now a Revit view that can be placed on a sheet and printed right along with the rest of the Revit project set.
First, get comfortable with the Revit environment, and learn to set up a project and add the grids, levels, and dimensions that will anchor your design. Then author Paul F. Aubin helps you dive into modeling: adding walls, doors, and windows; using joins and constraints; creating and mirroring groups; linking to external assets and DWG files; and modeling floors, roofs, and ceilings.
Paul also shows advanced techniques for modeling stairs and complex walls, adding rooms, and creating schedules. Finally, discover how to annotate your drawings so all the components are clearly understood, and learn how to output sheets to DWF, PDF, or AutoCAD.
- Understanding BIM and the Revit element hierarchy
- Navigating views
- Creating a new project from a template
- Adding walls, doors, and windows
- Adding plumbing fixtures and other components
- Linking AutoCAD DWG files
- Rotating and aligning Revit links
- Working with footprint and extrusion roofs
- Adding openings
- Adding railings and extensions to stairs
- Creating stacked and curtain walls
- Hiding and isolating objects
- Adding rooms
- Creating schedule views and tags
- Adding text and dimensions
- Creating new families
- Using reference planes, parameters, and constraints
- Plotting and creating a PDF