Revit 2026 - Moving a Curtain Wall or adding another wall on it's side adds extra grid segment on its own

[andrea.grillo]

I'm having quite the weird problem, and I'm pretty sure it was a thing also in older versions, but now has become unbearable.

I've created a Curtain Wall family where the grid is controlled by fixed numbers in instance properties, with multiple segment on the vertical grid and only one in the horizontal grid, wich I then offset slighly higher. 

At that point, no matter if I pin the grid, whenever I move or add walls to the side of it, it will add another segment on it's own. Without even changing the number of segments in instance properties, wich stays 1.

Meaning I now can't delete the segment I didn't want in the first place.

How can I be sure that, no matter what I do with the curtain wall itself (either moving it or adding walls on its sides) the software won't add extra grid segments or mullions to it?

I'll add to this post a few screenshots and an example file with the Curtain Wall I want to keep. You can try moving it in plans views or adding walls on its sides and replicate my issue, I confirmed it doesn't just happen in my main projects files, but even in a newly created one.

PS: Unfortunately I don't have older versions of Revit installed, thus I can't create a file with the same issues on those versions. If you wanna test it and you are on an older version, here's the step i took to recreate the issue:

1. Create New Project
2. Duplicate a standard Curtain Wall Type
3. Edit the horizontal and vertical grid options in type properties to "fixed numbers"
4. Create a new curtain wall with the new Type
5. Edit the Properties to have as may segment in the vertical grid and only one in the horizontal grid
6. Select the central horizontal segment and unpin it, then change the measurements to bring it up from the center
7. Pin it again
8. Now either move the curtain wall in floor plans or add a connected wall to it. The software will create again a grid segment right in the middle. It'll even create mullions if you have them set up in the Type.

[blank...]

I can confirm the behavior (don't know the solution, unfortunately).

But why can't you delete it. I just unpin newly created grid and hit delete. It gets deleted and the original one stays at the height it was set.

[andrea.grillo]

It is weird... Because in the original project file in wich was giving me the issue I wasn't able to delete it, even after unpinning the segment. The only differencse are that I had loaded a mullion family for the grid, because I need it for a shop facade, and that I am normally using the italian version of the software, with italian content. (I switched to the english version to provide information for the forum, since I'm not versatile in talking about architecture and revit in english, thus I needed the exact names of buttons, menus and compontents)

I've added a mullion family to the test file and even then I can still delete it, while I can't in the original project file.

I was also able to replicate the issue with mullions in a new stock file, but using the italian version of the software and family components. Maybe there's something wrong in how the mullion's family is setup in the italian version, because I can't replicate the issue in the english version. But I have no idea what the issue could be, since it happens even with revit stock families provided in the italian content. Even if I unpin the segment it won't delete. If I start by deleting the extra mullions first, when I try to delete the empty segment it will put the mullions up again.

I'll strip my original project file of sensitive customer data and provide that one, plus another new file created with the italian version (that has the italian content) and uses stock families for mullions. 

EDIT: I can confirm that the issue happens even with vertical mullions. Just set them to 1 and offset it from the centerline. When moving it or joining other elements to it, it'll create another mullion on the centerline that can't be deleted. I've also discovered that the moved mullions that remained in place can be deleted, meaning what's happening when moving the curtain wall is: 

The software reverts the curtain wall to it's stock settings, while still keeping the moved mullions too. That's why I can't delete the added mullions, the software thinks those are the only mullions present in the curtain wall.

This is really weird behaviour, and not something I can always keep an eye on when working on a building with several curtain walls all around.

[blank...]

Yup, don't know if there's some logic behind this behavior, but it looks buggy.

At least there's a solution. Sorta.

Create your curtain walls and set horizontal grid where you need it. Then edit type and for layout instead of "fixed number" set it to "none". When you click OK it'll warn you that some grid lines will be deleted. That's OK, delete them. Now you're left with just that one grid line where you placed it.

Good thing is that even if you first edit your curtain wall, and get those extra grid lines, you can go through the same process and they will be deleted keeping the one manually set.

Thanks to "arcanewindow" over at AUGI forum (see last post).

https://forums.augi.com/showthread.php?34202-Deleting-Curtainwall-Grids/page2

[andrea.grillo]

It does get the job done, meaning I don't have to constantly check if the grid and mullions change themselves by their own will.

But it's not something I would call a solution, since it's highly inconvenient to have to modify the family every time I wanna create a new curtain wall, and modify it back when I'm done setting up the grid as I need it. (Also it's pretty funny that you had to dig up forum posts from 20 years ago...)

It's indeed buggy behavior. Does the development team reads this forum? Or do I need to use other channels to report this issue?

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@andrea.grillo wrote:

(Also it's pretty funny that you had to dig up forum posts from 20 years ago...)

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I later remembered I had the exact same issue with vertical grids, and have that post saved on my PC 😁

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Does the development team reads this forum? Or do I need to use other channels to report this issue?

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You have to open a support case and report a bug.

[andrea.grillo]

Guess I'll try and do that, won't be the first time I manage to get the development department to replicate a bug and issue an article about it.