Revit Project Management: Interference Check for Clash Detection in CAD Teacher VDCI Video Series.

Using Revit's Interference Check for Clash Detection: A Detailed Walkthrough

Explore the process of utilizing Revit's Interference Check for clash detection, specifically between architectural models and mechanical elements. Understand the step-by-step procedure involved in identifying clashes, along with the limitations of internal clash detection with Revit.

Key Insights

  • The Interference Check, Revit's form of clash detection, is used to compare different elements in an architectural model, such as walls, with mechanical elements, including ducts and duct fittings.
  • While useful for a quick clash detection, Revit's Interference Check has its limitations, including the inability to run clash detection on two different links and the difficulty of identifying specific clashes visually.
  • The end result of a clash detection can be exported as an HTML file, but this might be difficult to interpret as specific clashes are represented only by an element ID number.

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Hello and welcome to the CAD Teacher VDCI video series for Revit Project Management. In this video, we're going to take a look at Interference Check, which is Revit's form of clash detection. So what we're going to do is we're going to clash the architectural model versus mechanical.

We're going to go to our Collaborate tab, and you can see all the way at the right here we have Interference Check. So I'm going to click on Interference Check, and then the option we want here is Run Interference Check. The only options we have are to run Current Project with a Link Project.

We can't run clash detection on two different links, so you can see if I were to say Categories from My Current Project against Categories from Mechanical, it'll give me the Categories from Mechanical and the Categories from Mine. So what I'd like to see is I'd like to see how walls work with the duct and duct fittings. So what I'm going to do is I'm going to just check Walls for right now, because if I were to go through and check too many of these, then it might be problemsome and I could end up with way too many clashes and it'd be really difficult to manage.

So I'm just going to stick with Walls for now, and then I'm going to go ahead and select Flex Ducts, Ducts, Duct Fittings, and Air Terminals. And let's see what we end up with. So Revit's gone through and done its Interference Check, and these are all the errors that it's showing me.

So right now it's finding clashes between the Walls and the Air Terminals, Duct Fittings, Ducts, and looks like nothing with Flex Ducts. But what I can do is, this doesn't really do me any good. It's really hard for me to see what I'm looking at here, but I can actually identify some of these clashes by looking for them within the view.

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So what I'm going to do is I'm going to go ahead and expand, say, Ducts. This first one right here. And let's see where it's clashing.

So it's telling me right now that this is the model, right? The link, category, family, and then this is the type that we're looking at. And the same thing here with my model. The Core and Shells, the Work Set, Walls, Basic Wall.

We can have it show us these locations, because it'd be really difficult to try and find them. You can see, you know, as I'm moving around, I'm not really seeing anything, mainly because we can't see through the Walls. So two things that we want to do.

We can select the clash, so it's going to find this element in another view. And I can click Show, and you can see it's showing me it here in the 3D view. If I click Show again, it'll show it in another view.

And it looks like it's showing me this clash right here. And that's one of the ones that we would want to investigate the rating of this wall and see if we need a damper or a different way of treating that penetration. But I'd really like to see this in the 3D view.

So I'm going to go ahead and switch back to my 3D view. And I'm going to change my visual style from Hidden Line to Wireframe. And that is pretty crazy looking.

So the next thing I want to do here is... Okay, so I want to select the duct that it's hitting. And as you can see, it's really hard to identify what I might be on. There's really no indication of anything being selected at this time.

So I'm going to go with the Wall. The Wall might give me a little bit better of a tip. And you can see here, it's actually showing me which wall is part of a clash.

Now I know which one is being interrupted. So what I can do is I can turn back to Hidden Line. And now I can use the section box to help identify the clash a little bit better.

So I know it's going to be the wall kind of along the ridge here. If I were to take my section box and adjust it back a little bit, I might be able to find the duct that they're referring to. If I click on Ducts... Nope, still kind of hard to see.

But you can see as we're doing this, we're actually identifying some other clashes. So you can see this isn't quite as smooth as running a clash detection in Navisworks, which is why a lot of people tend to just opt to do it that way. But it is good for a quick clash detection.

Another thing that helps is sometimes if you change it to Shaded View, you can see the actual element a little bit better because it's a solid color. And don't be afraid to do certain things to make it easier to see. So the roof isn't going to be part of our clash detection.

If I had that category off in this view, it actually might help me out a little bit. So for my visibility and graphic overrides, I can go to Roofs and turn off that category. And now I can actually see into all these systems here.

So I might be able to identify this exact clash a little bit easier. So it's not there. Could be on the first floor too because of how we constructed this model.

So I'll go ahead and adjust that section box one more time. And I'm going to bring it down just below the floor level here. Okay, could have gone too far with this one.

So I'll bring that out. Okay, so as you can see, as I go through the different clashes here, it's going to show me the category within our model that is being highlighted. So a lot of them are the same wall being penetrated.

You can see here we've got a clash with the duct. It's actually a little too wide for this wall. So that's a really good one because we'll need to pop this out to fit structural anyway.

And if we want, we can actually export this. And what you get is an HTML file that essentially looks exactly like what we see here. But it's a little bit harder to identify where the clashes are taking place because all we have to find them is this element ID number right here.

Okay, so let's say we wanted to run a clash detection between mechanical and structural because just visually here I can see we might have some major issues. If I go to interference check, select run interference check. And I want to run categories from structural.

Okay, and I'm going to select all of those. And then I want to run categories from a Revit link. Well, the way it works is we can only run clash detection from our current project and one of the links.

So this is kind of one of those, another downside to the internal clash detection within Revit. If we wanted to run a structural versus a mechanical, we would actually have to close this file. Okay, so first before we close anything, we always do a save to central.

Okay, and then open up the structural file. Okay.

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Michael Wilson

Revit Instructor

Bachelor of Architecture, Registered Architect

Mike is recognized by Autodesk as one of North America’s leading Revit Certified Instructors. He has significant experience integrating Revit, 3ds Max, and Rhino and uses Revit Architecture on medium and large-scale bio and nano-tech projects. Mike has been an integral member of the VDCI team for over 15 years, offering his hard-charging, “get it done right” approach and close attention to detail. In his spare time, Mike enjoys spending time outdoors with his wife, children, and dog.

  • Autodesk Certified Instructor (ACI GOLD – 1 of 20 Awarded Globally)
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