topic Re: Edit/ clean system family dimension style (R23) in Revit MEP Forum

Edit/ clean system family dimension style (R23)

sander.van.pelt — Mon, 08 Jun 2026 07:08:02 GMT

Hello everyone,

I am working on a project where there are 30 different types in a single system dimension family. This is despite the fact that only 9 (own dimension types) need to be present. When I look at the properties, there are nearly 50 variants listed under the Tick Mark/arrowheads. This is despite the fact that only a few of these need to be there.

They are many of the same types with just a different sequence number, but there are also many "SecretInternalTypePreviewArrowhead5478765182" in the list. All with the same naming convention, in other words.

How can I remove this "junk"?

Thanks for your help

Re: Edit/ clean system family dimension style (R23)

RLY_15 — Mon, 08 Jun 2026 21:25:05 GMT

If I recall correctly, Tick Marks are stored under the Arrowhead settings.

So from there, you're just doing using Purge Unused, but focusing only on the Arrowhead and Linear Dimension Style annotation categories.

Re: Edit/ clean system family dimension style (R23)

sander.van.pelt — Tue, 09 Jun 2026 05:56:27 GMT

Unfortunately, that is not the case.
If I purge the unused arrowheads, the list of different arrowheads remains just as long. This is despite the fact that, for example, "Diagonal 0.3969 mm" was also in the purge list; it is still selectable/has not disappeared.
So it is in use, but don't ask me where at all.

All dimensions we use in our model are of only 1 style/use only 1 type of arrowhead.

Are the arrowheads used in the links also displayed?

Re: Edit/ clean system family dimension style (R23)

sragan — Tue, 09 Jun 2026 14:45:50 GMT

I believe the secret..preview things were a revit internally generated thing. Or maybe a bug that has been fixed? What version of Revit?

EDIT: Opps, I see you are using Revit 23. They might have fixed this in more recent versions. See this long conversation, which I'm not sure was ever resolved:

Solved: Secretinternaltypepreviewgarrowhead - Page 2 - Autodesk Community

Yes, purging things like this can be frustrating, but I've usually found if you purge everything that is using that "type", you can usually purge that type.

The key is to create a copy of the file for "experimental" use. Then delete everything and purge, purge, purge away. If you can eventually get rid of these, you just have to find out what is using them, and then go back to your original file and do a more precision purge.

But sometimes it probably better to just pretend not to see any evil, and learn to live with it. There is a chance some of those will come back as the project progresses, even after being purged.

Re: Edit/ clean system family dimension style (R23)

Sefanja_Verkaik — Tue, 09 Jun 2026 15:46:38 GMT

So I tried to replicate the problem in Revit 2023. I can't find the issue. When I use Purge unused I can delete all the Tickmarks I do not want to have.

I would assume you first have to delete all the Linear Dimension Styles that you dont need. And make sure that none of the tickmarks are being used by any Revit Project Families. Before you can delete the tickmarks with Purge unused. When the tickmarks are being used by a Linear Dimension Revit wont give you the option to purge them out of your project.

Re: Edit/ clean system family dimension style (R23)

RLY_15 — Tue, 09 Jun 2026 18:54:11 GMT

You'll likely have to use the Dynamo method in @sragan 's link to pull out the 'secretinternal....' arrowhead types into a list and element.delete them.

Thankfully, this seems to be a version-specific problem.

Otherwise, @Sefanja_Verkaik is correct in that you'd have to purge out the associated Linear Dimension Styles to 'free up' any arrowheads associated to them, which would then be targeted in a second round of purging.

Re: Edit/ clean system family dimension style (R23)

pkomatlapalli — Thu, 18 Jun 2026 06:57:04 GMT

Hi @sander.van.pelt ,

Good day!

We would like to check back on this issue. Did the response from the community member Sefanja_Verkaik and RLY_15 help resolve the problem for you?

If yes, please click on the Accepted Solution button, It would be very helpful for others who may encounter the same issue in the future.

Thank you!

Re: Edit/ clean system family dimension style (R23)

sander.van.pelt — Thu, 18 Jun 2026 08:09:50 GMT

Hi Pavan Kumar

Apologies for the late reply, but due to my absence, I haven't been able to respond sooner.

When I run the script via Dynamo Player, I see in Dynamo that 65 element types are found. However, these are not removed; if I run this script again afterwards, the same types reappear.

Also, nothing has been removed from my list of arrowheads in Revit.

Am I doing something wrong?

Re: Edit/ clean system family dimension style (R23)

dbutts7 — Fri, 26 Jun 2026 12:39:40 GMT

Good morning, would it be possible to get a copy of the file to review and test? Thanks!

David B.