what does 'cutback' actually measure?

[mworthington6T5TX]

why does a cut back of 0 not mean the end of the beam I defined?

why do I need to set negative cutbacks manually to get close to  the point that should be defining the end of the beam? Why do Revit default families never do what you want? even for something as simple as a piece of wood. The beam isn't snapping to the Mass object (the line in the 2nd image which is actually a surface) so i have no idea what its trying to 'cutback' to on the other side. At least the side with the 'I' beam makes a little sense in its unintuitive way. 0 meaning the flange of a variable object it is snapped to, not the centerline where you define it....

Can someone tell me the way I'm suppose to think about this, I'm aware using Revit is an exercise in retraining your 'common sense' to whatever whim the developers had. but i can't figure out the thought process I'm suppose to be using here.

Got ~1300 timbers to adjust the lengths of. Apparently its not gonna be as easy as just dragging the end to the place I want. If I knew it was gonna be like this i would have just made my own line family when i put them in originally .... might still do that.

[ChandanSutradhar]

Beam cutback is the visible representative gap in beam geometry at the connection point in join relationships.

See this in detail for your reference: https://knowledge.autodesk.com/support/revit/learn-explore/caas/CloudHelp/cloudhelp/2017/ENU/Revit-M...

I think before you start modeling, we can set the value of cutback as 0, which will not create any issue of manual adjustment of each Beam already drawn in the wrong cutback. There are start extension and end extension, which we set as 1/2" default, and based on your project specific, you may set at 0 value.

As you have 1300 beam, need to adjust the cutback value to 75 if you know that is the same for all. Then please make a schedule of beams and change them quickly after exporting as an excel sheet and import the value by using add-ins of dynamo script.

[mworthington6T5TX]

I don't want to assume its the same for every instance since Revit is inconsistent at when the above issue happens. For the most part it was working as I expected. On Friday, I did it all manually over a couple hours. i figured out o could use the trim command and trim each beam on the mass family. Most seemed to behave well and only a few got 'end cut backs' while most have a null value. 1308/1324 are the same, the rest idk ill have to check each one and figure out if it's correct or fix it.

[mworthington6T5TX]

As I'm fixing each of these, I'm noticing it only gets a cut back when Revit thinks the beam is joined to something. If I drag the end away from the thing Revit presumably thinks I wanted it attached to, end join parameter becomes null. So will have to unattach each end before i can edit the cut back. thank fully its only a few now and my previous work for the most part was effective.

[ToanDN · Accepted solution]

Cutback is the physical distance between members, not the distance from the Analytical Node to the end of the physical member.

[mworthington6T5TX]

thank you, yeah I'm pretty sure I was only having issues because it was automatically joining the member to something filtered out in that view. Giving me weird behavior since it wasn't obvious it connected to something just from the visuals.

[adminG2B84]

I know this thread is from 2022 but I thought I'd share what I have learned as I was having trouble with this also. I hope it will help someone currently looking for the answer.

In my schedule I was using "Length" to make a cut list of beams and joists.

I found that using the "Length" field returns Revit's analytical length while "Cut Length" will return the physical length you would want to cut the beam to during construction.