topic Re: about rebar set in Revit Structure Forum

about rebar set

BJX916_XUANWU115 — Fri, 26 Jul 2024 02:09:26 GMT

Hi all!

I have created a rebar set in Revit, but we want the rebars to follow a slope at the top (shown in red arrow) and stop at the same level. Please see the section and elevation screenshots. I tried to use 'varying rebar' command, but the varying direction (shown in blue arrow) is not the one we want. Instead of adjusting the rebar one by one to meet the slope, is there any way to get the desired outcome more efficiently?

Many thanks.

Re: about rebar set

jay_colc — Fri, 26 Jul 2024 07:59:16 GMT

Really you need to be using Free Form Rebar placement in this instance and picking the Faces that will determine the slopes/angles and then edit the constraints to the Faces for greater accuracy if required.

Help | About Free Form Reinforcement | Autodesk

Re: about rebar set

BJX916_XUANWU115 — Mon, 29 Jul 2024 02:53:23 GMT

Hi Jay, thank you for your response.

I tried free form in this case before, but I got an undesired outcome. Please see below snapshot:

However, when you brought up free form, I thought about it again. So this time I created a dummy geometry as a host and then applied free form, the outcome looks fine to me.

I know we can apply constrains between free form rebars and the concrete surface or cover. But I wonder, could we add constraint between free form rebars and other bars? For example, I have two stirrup sets, they are both free form rebars. I want the distance between the hook of upper stirrup and the hook of bottom stirrup to be constant, say 500mm lap rather than 1832mm in the snapshot. But it seems that Revit doesn't allow me to add constrain between two hooks.

And then I tried another way. At this time, the hook of the bottom stirrup is constrained to the top surface of the host and the hook of the upper stirrup is constrained to the bottom surface of the host. In this case, the bottom stirrup works fine, but the upper one is flat at the bottom which makes the distance between two stirrup hook is less and less.

Then I tried to add constrain between the hook of upper stirrup and the top face of the host so that the bottom of the upper stirrup would follow the slope, but I got some tricky results:

The desired outcome should look like this:

Are you able to help with that? I would appreciate.

Many thanks.

Re: about rebar set

jay_colc — Mon, 29 Jul 2024 09:53:49 GMT

Hi,

Just to show Free-form does provide a solution for multi=planar slopes for readers.

You can constrain to other rebars but it adds a another level of complexity to the Free-From set and possibly can cause small rounding/placement anomalies, therefore I would suggest either using the default Host -Face as this is a known and works for the other sets or as I have seen recommend here also is a dummy host to use for placement and constraint and hide afterwards using visibility settings. I personally am not a fan of this but sometimes it has been the only solution for specific complex scenarios.

Re: about rebar set

BJX916_XUANWU115 — Mon, 29 Jul 2024 21:00:26 GMT

Hi Jay, thank you for you answer.

But Revit doesn't allow me to add constrain between free form rebars or between free form rebars and shape driven rebars, how do you achieve that?

Thanks.

Re: about rebar set

jay_colc — Tue, 30 Jul 2024 10:43:03 GMT

So in this example I have Varying Rebar for the Sloped Zone (Green) and Standard Rebar (Orange) for the main part of the element.

I picked the Varying Rebar > Edit constraints > Bottom Constraint > Hovered over the Top of the Standard Rebar

I picked the Varying Rebar > Edit constraints > Bottom Constraint (there are 2 references)> Hovered over the Top of the Standard Rebar Picked that reference and Edited the Offset Value

Re: about rebar set

BJX916_XUANWU115 — Tue, 30 Jul 2024 21:05:08 GMT

Hi Jay, thank you for your response.

It seems that the rebar sets in your example are both shape driven bars. But my problem is if the varying rebars are created by free form, and the standard rebars are created by shape driven rebar or free form, how can we add constrain between them?

Thanks.

Re: about rebar set

jay_colc — Wed, 31 Jul 2024 05:28:25 GMT

The only way i can get it to work as mentioned previously with Free-Form rebar you may need some dummy elements as they are assigned to surfaces/faces. In the example below I used a dummy element for the Standard rebar which allows the top face to control both the Standard and Free-form rebar position and then hide it in the model for the

Re: about rebar set

jay_colc — Wed, 31 Jul 2024 05:29:45 GMT

The only way I can get it to work as mentioned previously with Free-Form rebar you may need some dummy elements as they are assigned to surfaces/faces. In the example below I used a dummy element for the Standard rebar which allows the top face to control both the Standard and Free-form rebar position and then hide it in the model.

Re: about rebar set

BJX916_XUANWU115 — Thu, 01 Aug 2024 02:56:09 GMT

Hi Jay, I think I get the idea, you mean we can use an additional geometry to constrain the free form rebar rather than constrain the rebar to its host.

Actually I did a test yesterday and I got the desired outcome by using shape driven bars and applying 'varying rebar set' and rebar constrain which means we don't need to use free form in this case.

Cheers!