Author Topic: CID#910 Control Maximum Length  (Read 2408 times)

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Offline edvanTopic starter

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CID#910 Control Maximum Length
« on: Feb 05, 2026, 18:17:56 PM »
CID#910 is what we use for a wide variety of structural shapes and is certainly versital.
However, I have been fighting tooth and nail to figure out how to govern maximum allowed lengths.

For example: I don't want to product list the dimension governing length, because I need the part to be stretchable, but I would also like to restrict to not be stretched past a determined length.

I have been all over materials and specifications trying to get something to work to no avail.
CID 910 is type Rectangular/Standard/Structure/Equipment, everything but Pipework.
As far as I can tell, controlling max lengths via materials is somehow exclusive to the Pipework category.

Has anyone had any success with this?

Offline cadbyken

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Re: CID#910 Control Maximum Length
« Reply #1 on: Feb 05, 2026, 19:16:34 PM »
Length restrictions are part of specifications (pressure class on the duct side). See if setting up a material and length restriction for the Standard Library and see if that works for you. Note, with the different max lengths for each structural type, you would need different materials.
Ken Taylor - Atlantic Constructors, Inc
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Revit - not ready for Primetime given all of the add-ons, work arounds, and general issues with Fabrication in Revit.  Tired of them taking our money for little results.

Offline edvanTopic starter

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Re: CID#910 Control Maximum Length
« Reply #2 on: Feb 05, 2026, 20:06:42 PM »
Thank you for your quick response.
The example you provided shows a Specification entry for the Pipework library, which cannot be applied to CID#910.
Please see to my attached screenshots, hopefully they help make sense of my situation.

The Specification entry's "STD Straight" appears to have no impact on maximum allowed length. In my experience this is typically governed by a Material's Gauge, at least for Pipework.
However, these gauges cannot be applied to CID#910, as it is not a Pipework type.

Gauges in the "Duct" or "Other" categories do not seem to have any property to manage lengths, and inconveniently in my specific case, are only allowed to be "named" with numeric values.

I'm sure I'm doing something wrong here, the sheetmetal side of Fabrication is alien to me.

Offline PipeFitter72

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Re: CID#910 Control Maximum Length
« Reply #3 on: Feb 07, 2026, 14:25:24 PM »
the standard length in duct pressure class is the max length of a straight part when it is set to "Auto". the part will come in as that standard length and can be stretched shorter, but if you stretch it longer what will happen depends somewhat on your authoring software.  In AutoCAD another straight will be started. In Revit the part will stretch beyond the auto length. You then use the optimize lengths function to break it up into auto length + short leftover.  This applies to your straights for example CIDs 866, 40, 165.
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Offline edvanTopic starter

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Re: CID#910 Control Maximum Length
« Reply #4 on: Feb 09, 2026, 18:23:44 PM »
Thank you all for your replies.
I think CID#910 is a lost cause in this specific case, as it is neither Duct or Pipework and does not have a "Length" dimension that has functionality to support "Auto" actions.
The default value can be set to the maximum allowed, and it will be up to the user to ensure they don't exceed this value.

It would be nice to have this feature available.
According to Darren Young's Revit CID compatability log, 910 is still incompatible with Revit  ::) .
https://www.darrenjyoung.com/resources/autodesk-fabrication/revit-support-history/
So I'm sure it's far off the Fabrication team's radar...

You can't ask for everything I guess.

Offline dopefish

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Re: CID#910 Control Maximum Length
« Reply #5 on: Feb 09, 2026, 20:57:53 PM »
So the 910 i run just honors the number in the "height" property. I leave it unlocked and can stetch it wherever and it wont grow more than that number.
"And the wood header is still 4  3/4" on top of the top of the double top plate." . . . Random VDC Coodinator

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Offline AN-detail

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Re: CID#910 Control Maximum Length
« Reply #6 on: Feb 10, 2026, 14:47:42 PM »
Kind of a hack job, but if you put a dependency on the height dimension you can get the result you are looking for: stretch will reduce down but not increase past max height. See attached example with 48" max length.

Offline edvanTopic starter

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Re: CID#910 Control Maximum Length
« Reply #7 on: Feb 10, 2026, 18:00:57 PM »
Kind of a hack job, but if you put a dependency on the height dimension you can get the result you are looking for: stretch will reduce down but not increase past max height. See attached example with 48" max length.

This does exactly what I need it to do.
Thank you for your wisdom, AN-detail!

I had no idea the dependency assignment was a feature, or rather it's intended use.
I'm close to 8 years in and still learning every day.
As long as it doesn't interfere with how lengths are read in our automation tools, I will absolutely be rolling with this.