Rebar hook segment lengths

[semi]

Hi everyone,

is there some way in Revit you can automate the rebar hook segment lengths to adjust according to the diameter?

This was implemented in Autodesk Structural Detailing:

The hooks segment lengths would automatically change to the correct size when changing the diameter:

In Revit this has to be done automatically, but I was wondering if it could be automated as well?

Another question: when changing to another diameter the hook segment length also seems to change by mm?

If this happens, this means it CAN be adjusted right?

See below: the same rebar Ø12 changed to Ø14 results in hook segment length of 15,10 ???

[EdwinG]

In Revit you have hook lengths and different shapes of rebar in your example the parameter A is belonging to shape 11.

the hook lengths are automatically calculated see.

https://knowledge.autodesk.com/support/revit/learn-explore/caas/CloudHelp/cloudhelp/2020/ENU/Revit-M... 

[semi]

Hmm, not really, aren't those lengths for shapes defined by their A-B-C segment lengths?

Hooks are more used in the other method when you use a shape 00 and add a hook to it.

Even so I tried it out and set this:

changed it to Ø16 or Ø20 (doesn't change the hook at all):

which is normal imo because I'm not using any hooks (the shape does):

When I start from shape 00 and add a hook to it, it works fine like I said, but we use shapes (for reference to the schedule images). Else the fabricator would be confused.

adding a hook to it adds the length perfectly (20) but the rebar shape changes to "Rebar shape 01", which we don't want, because as you can see (Rebar shape 01 and every other rebar shape that will be made) will have "none" as image.

and yes this is checked as well:

[ovidiu_paunescu]

Hi @semi 

The hook length for each diameter is defined in the hook types menu.

If you set it to auto-calculation, it will use the hook length multiplier, defined in the hook type, to compute its length by multiplying that with the bar diameter.

If you want to report the hook length (for schedules and properties palette), you need to set one of the parameters with the formula to report Start / end Hook Length, offset length or tangent length.

I see you included the hooks in the shape definition. This means that when you add a hook to shape 00, a new shape will be created. If a new shape is created (in Revit 2021 or newer) the hook length should be added automatically to one of the shared params (A, B, C).

If you would not include the hooks in the shape definition, but would still want to report the length, you can edit the family of shape 00, without adding any hooks in the family, you can write a formula "=Start Hook Length" to one of the parameters. It will show 0 until you also add a hook to the bar.

To test any reports of the hook length, like in your first post, try to measure using a dimension placed manually on the bar, like it is depicted in the page below (for each hook bending angle) to see if the reported length is the same as what you are measuring.

https://help.autodesk.com/view/RVT/2022/ENU/?guid=GUID-5E2D4E9E-45D9-43E7-8E57-7BEFF4C9D9DA

[semi]

We only use shapes for scheduling, we never add a hook to a shape 00.

How come my hooks don't change to the asked lengths in the hook definitions as you can see in my screenshot?

Btw, in what situation would you not want to report the hook lengths? I don't understand why that is even an option? 

[ovidiu_paunescu]

I don't know why. Maybe add a simple model that has those bars and I can have a look.

Users who set the option to not include the hooks in the shape definition and add a hook to 00, such that it remains 00. If it doesn't have the hook length added to a formula then it won't report it.

Also if you edit an existing shape without hooks, add hooks inside the family, but forget to add the hook length formula to any of the shared parameters, that will not report the hook length either.

Of course the computed total bar length and bar length (for each bar) will include the hook length.

[semi]

Hi,

see attached revit file.

But if you only use shape 00 and "report" it has to have a hook, how will the fabricator know this if he doesn't have a correct shape image? Most of the time the fabricators here only look at the images and produce the rebar like it is shown on the image.

[ovidiu_paunescu]

Hi @semi 

You don't have hooks assigned at the ends of that family. A and C are driving the segment lengths. Their values change because the diameter changes and the dimensions are measured to the exterior of the bar.

To change this to hooks, you can edit the shape family, delete the two segments and add 90 deg hooks. After this, set the formula for A and C to be equal to hook length (or tangent length).

[semi]

I' ll try it out.

Strange though why Revit doesn't implement this in their shape families as standard.

Do know that these hooks aren't always the standard hook lengths, what do I do then? Override?

[ovidiu_paunescu · Accepted solution]

Well, you can set the length for each hook type, when placed on a certain diameter or you can define it to auto-calculate based on that multiplier and the value of bar diameter.

You can do that by type, to set it up for your project. If you want to use the hook as an end segment, you can override the hook length and manually input a value, just for some bars.

[semi]

it worked, but as suspected this results in this shape image generation in my schedule:

[ovidiu_paunescu]

This is what you need to do

[semi]

I know, that's what I did exactly but my shape image is generated by a 3rd party addin, so it gets messed up

+ it also messes up my AGACAD configuration. The tool now generates a Rebar Shape 1 instead of the 21 shape.