Can't change dimension segment to this value error.

[Anonymous]

I have used these forums an others for years now, and this is the first time I've been unable to find an answer.

This is a random issue (as far as I can tell), where I select an object and click on the dimension value, type in the new value I want it to have, press 'Enter':

"Can't change dimension segment to this value."

This has happened with model objects, reference planes, and design lines. The only thing that seems consistent is I'm usually in a plan view when it happens (but that's where I spend most of my time anyway).

Sometimes the problem is solved by shutting down and restarting, other times it persists through that. I have deleted the element and redone it only to get mixed results, sometimes its fine, other times it's still an issue.

Google pulls in a handful of hits for that exact error, but none of them have been helpful.

I have only been noticing it for the past ~12-18 months, but it's starting to get to me. I would really appreciate some help.

Thanks

[L.Maas]

Best would be if, when you find such a situation, is that you upload relevant part of your project so that we can have a look.

Does this happen to a particular project or to projects based on the same template?

When this occurs have a look if there are constraints in place. 

If possible check if it also happens on another computer.

Have a look at updates (Revit, Windows, graphics card).

If you can not easily replicate the problem it might be a bug or a slight corrupt project (template)?

When you upload something do not forget to mention which Revit version you are using.

[barthbradley]

I'm thinking HIDDEN CONSTRAINTS. Does Reveal Hidden Constraints show any?  

[Anonymous]

Hi Louis,

Thanks for you response.

We are now using Revit 2018.1, bt I have had this happen in 2017.2 and possibly 2016. I opened the project  on another PC and the issue was still there. However when I shut down Revit and restarted it on my own it was fine. My inability to recreate this issue reliably is pretty annoying...

The model is too large to upload, and I cannot recreate the issue by copying and pasting the element to a blank template. I have attached a screen shot of the error though. I tried looking for hidden constraints but could not find any relevant ones. I changed the highlighted dimension value from 300 to 400 which i thought would be pretty safe.

We have been using the same template in the office for many years, so that could be part of the problem. No one else has encountered this before though...

[ToanDN]

What is the element you dimensioned to?

[Anonymous]

In that image it was to a basic wall. I also moved it to a reference plane in the door family, and a nearby design line with the same result.

[ToanDN]

I mean what is highlighted below?

[barthbradley]

@Anonymous: are you, by chance, pulling a dimension from a link/import element? 

[Anonymous]

@ToanDN that element is a design line.

@barthbradley There is a linked model in this project but it is positioned away from where this is happening.

[ToanDN]

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@Anonymous wrote:

@ToanDN that element is a design line.

@barthbradley There is a linked model in this project but it is positioned away from where this is happening.

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Design line?  I assume you mean either a Detail line or a Model line created in the Revit file.  Yes?

Or is it a line from a CAD link/import?

[Corsten.Au]

Hi

Isolate exact elements you need to change, respecting each other elements.

then try to dimension and change.

Cheer!

[VincentDiBiasi5378]

OK, this is a frustrating problem. "Can't change dimension segment to this value" slows things down and takes away a tool for working fast in Revit. Can the Experts please open up a 2019 or 18 version of Revit and see if they can duplicate the problem and then fix it, please.

Thank you

[Anonymous]

If anyone has found a solution to this issue, please post it. It is incredibly frustrating.

[Anonymous]

I had the issue when I was adjusting a wall dimension from floor plan view, but it resolved after I adjusted it from section view.

Hopefully that helps!

[Anonymous]

No joy for me. Thanks though

[gbielicka]

I too am having this problem. So very annoying. AUTODESK respond!!!!!!

[ToanDN]

Post a screenshot of the elements and the dimension you are having trouble with.

[Anonymous]

This happens to me when I change the witness lines. E.g. when adding a short wall to a bedroom for a closet, setting the witness line to be the faces of the new wall and one of the bedroom walls (for an inside-to-inside dimension, so nobody has to do math when the walls are different widths). It looks like this is causing Revit to over-constrain the model by treating two witness lines as mutually exclusive constraints. It is clearly a bug, and so easy to reproduce that I can't imagine AutoDesk isn't aware of it. Given the type of bug there are probably multiple ways the to force it to manifest.

Now if I could just figure out how to get Revit to set the face of the wall to be the default witness line takeoff, instead of center to center....

[Anonymous]

The same thing is happening to me in Revit 2019.

[barthbradley]

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@Anonymous wrote:

The same thing is happening to me in Revit 2019.

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Are you buying into the "it's a bug" explanation? It isn't. If you want to start a new thread citing your own circumstance, perhaps we can troubleshoot and provide a more likely explanation.