NOTE: The exercise files for this course can only be opened in the most recent version of Revit (Revit 2017).
Skill Level Appropriate for all
- [Instructor] This week I want to talk about corner mullions. There are four built-in corner mullion conditions that you can apply wherever two curtain walls join up with one another. And the nice thing about these corner mullions is they'll actually react to the curtain walls as they modify. So, if you change the angle between the two curtain wall segments or make any other adjustments to the curtain walls, those corner mullions will adjust accordingly. I don't have those assigned at the moment. What I have is just the standard curtain wall design here where if you select it and you go to Edit Type, all of the mullion conditions are just using the default rectangular mullion, 2.5 x 5 inches.
So, if we look at it here, you can kind of see that it's not joining up very well. And then I've got a mullion detail right here that shows it even better. And you can see very clearly that we've got some overlapping geometry. Now, your first instinct might be, well, just use the Join Geometry tool. But unfortunately Join Geometry does not support the mullion category, so we're not able to select that geometry at all. So, that's unfortunate. So, what do we do instead? Well, let's take a look at these corner mullion conditions that are available and discuss what the pros and cons of using them are.
So, I'm going to make this change at the type level. So, I'm going to select one of the curtain walls themselves, go to Edit Type, and scroll down. And I'm going to focus on just the Vertical Mullions, Border 1 and Border 2. And when I open up this list here, you should have some corner mullion options available on the list. There're in the built-in out-of-the-box template. So, I'll start at the top here with the L Corner Mullion and I'll assign that on both sides and click OK.
Now, I'll get this error message here because Revit will now recognize that making this change would end up with redundant mullions, sort of overlapping mullions, and it's offering to delete all of that overlapping geometry. So, I'm going to go ahead and do that. And I get this nice clean condition now that no longer has any overlapping mullion geometry. So, it's certainly solved that problem. The result of the L Condition is a little bit bulky, right? So, you might want to look at this and say, well, what can I customize here? Is there anything I can modify? So, I'm going to select this mullion here and go to Edit Type.
And there's really only two properties. There's an offset and a thickness. Now, the offset will actually shift this thing along the thickness of the curtain wall in both directions. So, if we click Apply here, you kind of see it almost moved along a diagonal. So, probably not what you want to do. I think you're probably going to want to leave that at zero. And then of course the thickness is just how big the actual mullion itself is. And you really ought to make that match your other mullions. So, leaving that at five inches here makes a certain amount of sense for this example. Unfortunately, we don't have any control over this distance and this distance.
So, we're kind of stuck with how long these L Legs are, which is a bit disappointing in this respect. Alright, so let me click OK there. And let's move on to the next condition. So, I'll do Edit Type again and instead of L Corner I'll switch to a Quad Corner. And click OK. And now this is a little less bulky because it just creates a square, basically. Now if we tab in and select that and edit its properties, it's got the same offset parameter, but notice it does not have the thickness this time.
So, it will always match the thickness of the surrounding mullions, which is kind of interesting that the L we could change, but the Quad we can't. So, once again, if you're satisfied with the properties of the corner mullions, they work great. But if you want to customize them in any way, as you can see, customization potential is at a minimum here. Let's look at the other two possibilities. So, we've also got Trapezoid.
And I'll just click Apply, and that kind of creates this big chamfer condition here. And then we also have V. And I'll click Apply. And that's kind of the opposite of L. Now, once again you can explore what the modification potential is in both of these, but it's going to be somewhat limited. You can't customize the profile of these. You can't customize the shape of the geometry, so the shapes are built-in, they are system families essentially, and other than those offsets and thicknesses, you really have very little that you can customize.
Now, all four corner conditions will respond to the angles of the curtain wall. So, I'm actually going to set this back to the Quad Corner here to illustrate this, but you can do this really with any one of the four shapes if you want to. And I'm going to go to the Level 1 floor plan. And zoom out here, select this short leg, and change the angle. And it doesn't matter what angle you change it to. Notice that the Quad will adjust, or any of the corner conditions will adjust, accordingly.
Now, I have two small problems after doing that. One is that this panel for some reason did not respond. I'm really not sure why that it is. It happens frequently, but it's easy to fix. I don't know if it's just a little fluke here. But if I select this mullion, unpin it, and then pin it again, that usually fixes the problem. So, I'm really not sure why that's necessary, but it only seems to be a problem when you change the angle. Again, seems a bit of a fluke there. Now, here this is the lower mullions, and at the moment they don't seem to be responding, so let me show you that in 3D.
That's a real easy situation here. The join condition of these are joined together in ignoring the vertical. See how the vertical is actually sitting on top? And they're not actually creating a nice tight corner there. But if you just toggle that join condition and let this vertical come down, that solves the problem. Okay, so, I think that's probably more appropriate anyway. So, that should be an easy fix as well. So, those are the corner mullion conditions. Now, what I'm going to do is change this angle back to 90 degrees.
And again you'll see the mullion respond, but for some reason I have to pin and unpin to get that panel to behave. Okay, so, there's our corner mullions. Now, let me go back to our mullion detail. And what about a 45 running along this diagonal? They gave us all the other conditions, but they don't have that, which is one of the most common conditions in commercial buildings. So, unfortunately we don't have a built-in corner mullion for that condition, which is definitely disappointing. So, what can we do about that? Well, you might be tempted to use a standard mullion.
If I select any one of these mullions here, and I'm going to go right to Edit Type, and instead of duplicating, I'm just going to change it directly just to show you this. When I click OK, there's an angle parameter, and you can rotate a standard mullion to any angle that you like. Now, interestingly, notice that the lower mullions are responding to that new angle and chamfering and cutting with the angle of the verticals, but unfortunately the panels are completely ignoring that condition.
So, while it's possible to do that rotation, couple that with an offset, couple that with adjusting the lengths of the curtain walls, and you might get that mullion in the corner to be close to where it's supposed to be and geometrically correct. The panels will always be a problem. So, you can certainly fiddle with it and it's somewhat tedious, and you might get there, you might get a condition that's acceptable to you, but I doubt whether or not the amount of effort that you have to put into it would be worth the result.
So, I'm going to undo that. And put all that back again. And what I want to do now is show you what a lot of folks will do as an alternative. So, I'm going to zoom back in over here at the corner, select the curtain wall, go to Edit Type again, and I'm going to remove the Quad Corner and set both verticals to None and click OK. So, here it will recognize that I have a bunch of vertical mullions that need to be deleted, so I'll click Delete. And now I end up with a corner here without any mullion at all.
So, what we can do instead is we can substitute in a custom element. Now, unfortunately if you go to File and New Family, you will find that you cannot create a custom mullion family. Mullion families are system families and they cannot be customized in the family editor. So, what's your alternative? Well, you can go to File, New Family, and you can create a Curtain Panel family. And folks do this very frequently. So, when you create your own custom Curtain Panel family, if you choose to, you can actually build geometry that represents a mullion directly in the panel family.
Now, a downside of that is that mullion will only be a mullion graphically. Revit will not actually recognize it as a mullion. So, if you're trying to count how many mullions you have or otherwise use the mullion category, these corners will not respond as mullions. They are part of the panel. So, that's a potential downside. But assuming that that's not an issue for you, then all you need to do is just build that mullion geometry directly into the panel. So, I'm going to select this panel, and notice I can't change it because it's part of the type.
So, I'm going to unpin it to get to the type selector, open that up, and I've created an example of a panel like this that I called Panel with Corner Mullion and placed in this file. Now, the corner mullion went in over here on the wrong side, but I've got these flip grips here, or you can just tap the Spacebar. But I'll just flip it that way to push it over here. And then I'm going to go to my mullion detail view so that we can take a look at that a little bit more closely. So, you could see the way I created it was with this little pocket here and the panel kind of shifts into that, but of course I've got a little gap on this one.
Well, all I have to do is tab into this panel now, unpin it, and assign it to the same panel type and that completes the effect. Now, if we return to 3D, that only applied down here at the first level. Notice these upper ones are not applied. So, turns out it's very easy to fix this, just tab in to the panel, any one of the panels at the edge here, Right Click, go to Select Panels Along the Vertical Grid. That will select all of them up the entire length of your curtain wall.
Unpin them with this tool right here or type U + P. And then you can change them. And then I could repeat that over here, tab in, Right Click, all panels, and unpin them, and apply them here. But of course, those are going to be pointing the wrong way, so I'll remove this one and then just tap the Spacebar until they are pointing the correct way. So, pretty easy to get those assigned at the... All the way up the curtain wall.
And as you can see, the effect is quite convincing there with that corner mullion. Now, the way I built this one, I built it at 45 degrees. Which means that if you did come over here and select the curtain wall and change the angle, those will not respond. So, you would need to know which angles you need, go into the family editor, and build each condition. So, you could have a 45, you could have a 60, you could have a 55, whatever angles you need. Now, if that's not satisfactory to you, I think in many cases that's perfectly appropriate if you only need two or three angles, it's very easy to do.
But if that's not satisfactory to you, then your alternative is to create a very complex family that has built in angle parameters and then lots of formulas to flex the geometry to any angle that you like. Now, you're welcome to embark on that if you wish, but I personally think it's a situation of weighing the pros versus the cons. Is the amount of effort that it takes to build a highly flexible curtain panel family like this worth it compared to the number of angles that you practically need in any given project? And I'll leave that up to you to decide.
So, your choices of dealing with these corner conditions are to use the built-in corner conditions if they work for you, if they match what you need. And if not, then the very common workaround is to simply build the mullion geometry directly into a custom curtain panel family.
Q: Why can't I earn a Certificate of Completion for this course?
A: We publish a new tutorial or tutorials for this course on a regular basis. We are unable to offer a Certificate of Completion because it is an ever-evolving course that is not designed to be completed. Check back often for new movies.