Unjoining a structural column

[Anonymous]

In my design I have two beams with a mitred joint. All good. Then I add a structural column under the joint. The column immediately connects to the beams and the mitred joint is broken. Apparently the column is joined to the beams, not attached, because when I click "Detach Top/Base" in the column modify tab the "Detach All" button is disabled. If I choose "Unjoin" from the geometry tab I can't select either the beam or the column, so that is clearly not the right tool. If I shorten the column it will unjoin from the beams, but as soon as I extend it so that the end is near the beams it will automatically connect again.

How do I tell the column not to connect to the beams? Or, alternatively, how do I allow it to connect but preserve the connection between the beams? This has bugged me for years, actually. Usually I end up extending the beams beyond the column and then using reference planes to cut the mitre, but this is a right PITA.

Using Revit LT 2016.

[Rafal.Gaweda]

Hi Bruce

I hope you meant this:

[Anonymous]

Thanks Rafal, but not really like that. Your concrete beams are not really mitred, and if they were you probably couldn't tell. Here is a video capture showing creation of two beams, mitring the joint, adding a colum, moving it under a beam (which causes it to join to the beam), then moving the column under the beam junction. The beam junction is broken. If I shorten the column the column/beam joins are broken and I can mitre the beams again. Then, when I lengthen the column so that it is close to the beam junction, it again connects to the beams and the mitre is broken.

[ToanDN]

I don't know how to draw a column under the beam and they get joined automatically.  None the less, if you can draw the columns shorter or longer and use attach top base or cope to extend them to the beam.

[Anonymous]

Hi ToanDN,

Try it again but put the column underneath the beam junction. When you attach the column to the beam it automatically joins to the beam and detaches and the beams cut back. The distinction between join and attachment is a bit confusing.

[ToanDN]

I see what you mean.  I am not very familiar with Revit Structure so I don't know of a way to disable automatic joining when column is placed at beam intersection.  But I do know that fixing it after the fact is quite easy.

[Anonymous]

Hi ToanDN,

I followed your capture closely and tried to duplicate it but it doesn't work for me. When I attach the top of the column to the beam the mitred joint is broken and I get a warning "The column and target are joined. The attachment has been removed". Could it be a difference between my Revit LT 2016 and your Revit 2017? I notice that the tools in the structure tab are a bit different from mine.

[ToanDN]

I tried to do it in Revit 2015 and it works the same (file attached).  But I do not have Revit LT so I cannot confirm.

[Anonymous · Accepted solution]

Hi ToanDN,

Thanks for providing your model. The difference between our models is that your beams were top justified and mine were bottom. If I bottom justify your beams and then attach the column the beam intersection is broken.

I can't think of a good reason why the z-justification of the beam should change the column join behaviour but at least I know I am not going insane. Unfortunately my beams are almost always bottom justified. I suppose I could add another level for the top of beam but I try to avoid having a lot of levels. I think I will stick to using reference planes on the mitre line and cutting the beams for now.

Thank you very much for your time.

[sumyat.paing]

Hello

I am attempting to model a pile cap. But because its a footing family, it moves to the bottom of the column... Is there a way to disassociate my pile cap from attaching to the bottom of my colomn?

[Base12]

I run into this problem all the time and often reducing the height of the column solves the problem but in this case and sometimes others it does not.  You can see that these beams and columns are obviously not connected, but Revit thinks they are.  Using the Unjoin tool does nothing.  Changing the height of the column above or below, etc the beam above doesn't remove the join. Wtf?

[Base12]

Every.  Single. Time.  I'm seriously at my wit's end with this f***ing garbage.  I waste so much goddam time fighting this it's sickening.

[ToanDN]

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@Base12 wrote:

Every.  Single. Time.  I'm seriously at my wit's end with this f***ing garbage.  I waste so much goddam time fighting this it's sickening.

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Re: Columns won't attach to beams - Autodesk Community - Revit Products

[aashford3Q2J4X]

check out my reply to a similar issue.

https://forums.autodesk.com/t5/revit-structure-forum/join-beam-columns-tool-not-showing-arrows/m-p/8...

[Base12]

that is a good read and offers a lot of insight... but it does not answer the problem of the Revit error "remove that join before attaching"... how does one "remove that join"?  Sometimes just making the column shorter removes it, but sometimes it does not... not sure why.  In my screen shot they would absolutely not come apart and everything I did produced that error.  Ultimately I had to just delete them and draw new beams off to the side (at the correct level, but out in space), manually disable the end joins,  and then move them to be correctly positioned in the model.  This cannot be the expected work flow unless Revit is so specific about "model it like you would build it" that it involves placing the beam on your job site and then crane it into place!?  Every other method of drawing the beam I tried just grabs whatever column is nearby willy-nilly and then never lets go to even start with end joins or coping, etc.

[aashford3Q2J4X]

I've actually never seen that error, and I'm trying to reproduce it without any luck!

There must be some element in your model or process that is causing this...
Is this a Revit 2021 - 2023 issue? I'm in 2024.
Which Family are you using for the columns and beams? (things like concrete and wood act differently. e.g., concrete doesn't stretch at the ends, like wood and steel.)
Do you move elements with the dis join on or off?

When drawing my columns, and then my beams, everything is joined and I'm just dealing with clean up mainly for rendering purposes. (miter or cope) I can get a "can't, keep elements joined" warning, if lets say i move the beam in elevation to its desired height, disconnecting it from the columns below. But then I need to raise the columns to the underside of beam using the level and its level offset settings.

When I have complex roofs, or important structural lines I'll create a level or reference plane to align object to. This helps control the model and give parameters to objects.

I was also wondering if your file is using any phases or design options and if anything is colliding. For example I have a lot of the time, Existing condition model, demo, and new as phases. But the new and old walls are doing something weird because its colliding with a another object from another phase. If you do not have any phases then this isn't a thing.

Perhaps you can post a small file version, a recreation of the issue. And describe how you draw/place your column, then how you draw/ place your beam, and then describe what you do to get that warning. A screen recording with audio is another alternative.

hope i can help find a solution

[arulewich]

For those who, like me, may have been scouring message boards looking for a way to prevent beam/column joining (either because of messy joins or in my case getting the dreaded "unjoin column and target" error message...). I found a solution buried away in another thread:

Select the offending beam. Right click the blue control dot at one end. Select "Disallow Join", much as you would with a wall. The end of the beam will no longer be attached to any columns. Repeat at any offending beam ends. 

Yes, it means you have to select every single beam and right click each. Yes, there appears to be no way to disable automatic joining by default. Yes it will also reverse the direction of any extension offsets (a negative offset becomes a positive one...). But why would Revit make our lives easier?