Join Paul F. Aubin for an in-depth discussion in this video Creating topography from a DWG link, part of Revit 2018: Essential Training for Architecture (Imperial).
- [Instructor] There are many scenarios where you might need to use imported data from other programs in Revit and one very common scenario is when you're working with a civil engineer. There is no Revit Civil Package. So, civil engineers are often working in AutoCAD Civil 3D or MicroStation. So, if they produce a file that you want to use in your Revit project, it'll come in in one of those file formats. So, in this video, I'm going to link in a CAD file that represents the site plan information for my project and then use that to create a Revit element called a toposurface.
So, I'm going to get started in the site plan actually because the display characteristics of the site plan are more suitable to the information that I'm going to be bringing in. Then I'll go to the Insert tab and I'll click on Link CAD and I'll single-click the AutoCAD Siteplan file that I have listed right here. Now, if you watched the previous video, we imported a floor plan. I'm going to use largely the same settings here but I am going to modify one or two things. So, for the colors, I'm going to choose Invert. I'm going to bring in all the layers and I'm going to auto detect the units.
I will bring it in at Origin to Origin but the two things that I want to change is you may recall that in the previous video I mentioned that if you have really large files and particularly civil engineering files where there's a lot of irregular shapes and curves and so forth, that Correct lines that are slightly off axis might actually cause some round off errors and some other problems. So I'm going to uncheck that checkbox right there So we're not going to correct those lines that are off axis. And then the other thing that I'm going to uncheck is the Current view only setting.
So, what this means is it's going to bring in this CAD file and preserve it as in actual model element. Now, this CAD file has contour lines that are placed at different Z height. So if I did not uncheck this, it would actually flatten out all that data and turn it into 2D in view specific. So I want to preserve all that Z height information when I bring it in. So make sure that Current view only is unchecked, Correct lines off axis is unchecked, and then all of the other settings, I'll just accept those defaults and click Open.
Now, it's a very big file and if I do z + f to zoom to fit, you're going to see that it's very large and where we were just zoomed in was a very small area right around here. Now I'm going to type z + p to zoom previous and what I want to do at this tight level of zoom is talk about what's actually contained in this file. Now, I'm going to select the file and you notice that that will highlight the entire thing. If you're unable to select the file, then you need to come over here to the select dropdown beneath the Modify tool and make sure that both Select links and Select pinned elements are checked on.
If those are unchecked, you won't be able to select the file. Now, notice that there's all these different lines that represent the contour lines within this file. What I can do with it selected is use this Query button here on the ribbon. This allows me to actually reach into the file and query the individual elements contained within it. So, I'm going to click on one of these contour lines here. It doesn't really matter which one. And what I'm interested in is the name of the layer. So you might want to jot that down somewhere so that you have that information.
Now I'm going to click OK and then notice that there's a second layer here with a slightly different color. So I'm going to click that one and that one has a slightly different name. So there's actually two different layers that contain contour information. So I want to jot down both of those layers and make sure that I know their names and then click OK. Now, I'm still in the Query mode, so let me click the Modify tool to cancel out of there. All right, so, the next step is I now want to begin creating a toposurface. So I'm going to do zoom to fit again, z + f, and let me show you what a toposurface is first of all.
So, on the Massing & Site tab, there's this Toposurface button. When you click that, it will gray out the drawing temporarily and it will put you in in Edit mode. Now over here, you'll see that there's a Place Point button that is currently active. On the Options bar, there'll be an Elevation height for the point you're about to place. So, if you want to, you can create a simple toposurface by just creating multiple points. If you come over here and change the height of that point and place additional points, it will begin creating topography at a particular slope and you can see how it's creating all of the gradations in between.
Now, if you have a very simple site object, that's the quickest way to build that site object is to just set a few elevations and place a few points and let Revit interpret all of the contours in between. The trouble is, looking at this file, it's huge and there are thousands of points. So, that's not really going to give me what I want. So I'm going to pick this big, red X here and cancel the command. It's going to warn me that it's going to throw everything away and I'll say yes. And then let me repeat the command and this time, instead of using Place Point, I'm going to go to the button next to it, which is a dropdown button and choose Select Import Instance.
Now this allows you to simply select the CAD file and then that will display a dialog with all of the layers in the CAD file listed. So, what I'm going to do here is uncheck the two layers that I wrote down from the Query command and then click this Invert button here to reverse all the check boxes. So I only want those two layers selected and none of the others. When I click OK, Revit will process those two layers and it will create the thousands of points for me based on the heights of the geometry on those two layers.
So this is an incredibly powerful tool. And if we zoom in here, you can see just how much work that did for us. Now, if you imagine trying to place all of those points manually, that would be a tremendous task that would take potentially hours. So this happened in a matter of moments. And now, when I click the Finish button, it will create a toposurface from all of those points. Now, the best way to see this toposurface is to come up here on the Quick Access toolbar and click the default 3D view button to go to a three-dimensional view.
Now, the CAD file is still right here and at the moment, it's a little bit difficult to see the toposurface that we created on top of it. So what I'm going to do is select the CAD file first. Down here on the View Control bar is a small sunglasses icon. If you click that, you have an option to hide the selected element. So I'm going to choose Hide Element and that will put us in a Temporary Hide/Isolate mode. And so, whatever you have selected will become invisible temporarily.
I can now zoom in on the toposurface, hold the Shift key down and orbit if you like. Zoom in a little bit closer. And then to make this even easier to see, I'll change it from a Hidden Line mode to a Shaded mode. And then you start to see a little bit of shading on here and a little bit more contrast. You can see that there's dips and valleys in the there and high points and low points. And if I use the View cube here and go to, say, a front view, you can clearly see that there is a slope going across the entire surface there with high point over here on the left and a low point down there on the right.
So, we now have this land surface here that we can begin building our Revit geometry on top of. So, if you ever want to create a toposurface quickly and accurately from CAD data, it's as simple as linking in that CAD file and then creating a toposurface from the layers within that file.
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