Metal Building Structural Frame - add an " Apex Haunch"

[HVAC-Novice]

I have the attached metal building frame family I found somewhere. I made it to look like the real frame. This is for an HVAC project, so it has not actual structural property in my model. i just need it so i don't run ductwork into structural members and for context etc. 

i hope I'm using the correct term... The " apex Haunch"  i need to add is the yellow-highlighted re-enforcement at the peak 

in the family i would have to edit the profile like the red-line:

I'm not too experienced with sweeps... I tried to add  a refence plane that could use. but i can't really figure out how the current sweep actually works (like what determines the slope?).  My other idea was to add a tri-angular extrusion to fill out that area. but that wouldn't look good. 

I searched for a frame that already has that build in, but couldn't find one. 

I know I'm overthinking this... but it bothers me that the frame doesn't look like it should. Could someone point me in the rights direction? 

[SteveKStafford]

One quick way to tackle it is with three extrusions; top flange, web and bottom flange. Create a framing family using the truss template. In the side elevation extrude the web shape and then sweep the flange profile along the bottom and then again on the top. You'll have the basic form you want for representation. If you only have the one size, don't even worry about it being parametric.

To build it as a sweep you'd have to define several swept blends and sweeps. A sweep can't change proportions along the path. A swept blend starts with one profile and can end with a different one. Three basic extrusion are fewer than the number of sweeps/blends you'd have to build to represent it.

[HVAC-Novice]

Thanks for the response. Do you mean the chords when you say flange? I'm sorry, I don't have experience with the truss family creation (I barely use the oob ones to place in my models). 

Do you mean I have to create that triangle as truss and place under the peak? I tried something similar with an extrusion in the frame family itself. But I didn't really find out how to constrain the geometry. and yes, I wanted it parametric so it works in multiple situations. 

I noticed this particular family use sweeps next to each other and each sweep includes the vertical and the sloped roof section. Some other frame families use different sweeps for the vertical section, and for each roof section. Maybe those are more conducive to do what I want by just adjusting the sweep. I also had the idea to have separate families for the verticals, and the roof part of the frame. but that will be harder to use. Depends on what actual frames I come across in the future. Maybe I have to create one from scratch, (and nested vertical frame families) to have full control and understand how it works. 

This isn't really mission critical for my project, I just wanted to go the extra mile to show it more exactly and learn more about frames. Looks like this is an extra 10 miles :-0 

[SteveKStafford · Accepted solution]

An I-beam has a flange (top and bottom) and a web, the portion that spans vertically between the flanges. Chord is also used to describe the top and bottom (flange) of structural truss. Functionally the "same", just different words for "beams" vs "trusses".

I'm suggesting you create, from scratch, the web as an extrusion (side view), the whole structural assembly. Then you can sweep a profile that is equal to the shape of the flange along the bottom and the top of the web extrusion. You'd define the path of the sweep as the top edge, sketch the profile of the flange in the perpendicular view Repeat for the bottom flange.

I also modified the family you shared. It's built the way I described for the most part. The trick to make it really work is adding parameters to define where the horizontal portion starts and ends. I didn't take time to test that out...

[HVAC-Novice]

Thanks so much for sharing. If I understand it correctly, with your family I would have to manually edit the shape depending on how the actual situation is? I just want to make sure I'm not missing some feature. At least this is how it looks to me when editing the family. My original plan was to have some parameters to control the size of the haunch. But I think this isn't easily done. The " rise" parameter doesn't seem to work anymore. I now realize I had it set to " type" instead of " instance". 

I actually found some other possible "solutions" . I just go the "Revit 2024 Black Book"  (highly recommended). It mentions the " connection automation". What it does is open some canned dynamo scripts. Unfortunately this seems to be meant for actual beams and not for my structural framing family. But I wanted to mention it anyway in case someone comes across this and models those frame with actual beams.

Next thing I found in the " Black Book" are Fabrication steel plates. It basically is a model-in place component that attaches to the  plane of the structural frame. It kind of would work like the family you edited since I have to create that per project. And i also have to include it in the array of multiple frame elements (or copy it with each frame). but it would keep the original functionality of the frame family (rise etc.). it also could be used for other frame " bulges"  that make the actual frame look different than the original family. Like Eave haunches, or an actual apex haunch or a mid-span haunch. I think that could be a tool for more complex frames. 

This is how it looks like. The downside is, it doesn't blend in with the frame. " join"  doesn't work since those are different categories. It fulfills it function of telling me to not run a duct in the space, but it will be visible where I " cheated" 

Some more caveats compared to your solution: 

- Have to create it with the first frame (along with the column) and then create a group or array (for multiple of the same frame). Actually it seems the plate cannot be made part of an array or group. 

- I suspect most view templates don't have those plates visible (Mine didn't). Need to set sub-category " plates" to be visible

with the inability to be grouped, the plates may not be as useful to me as I hoped. 

[ToanDN]

Like this?

See attached.

[SteveKStafford]

Most the buildings I've been that use a frame like this have beams that are fabricated into the form you have in the family you shared original, the haunch built into the overall form. There are usually connection plates, such as at the top of the "column" section, or just past the column. Then the roof is often in two or three pieces. All meant to make it fit on a truck's trailer. So you could go that far or stop short with a single family frame. It just depends on your patience (and your boss if any) and desire to model it like it gets built.

[HVAC-Novice]

ToanDN: yes, like that. It seemed using a storefront system is a model-in-place type situation. This gave me the idea to "model in place"  a structural frame:

When copying the frames I noticed when using " constraint"  it only moved along the up/down direction (90° to how you would copy such frame). But without constraint I could copy it. Creating an array for some reason didn't work in the correct direction either. I assume it is related to the plane the in-place family was created. 

It seems to create a new family in the browser every time I copy it. 

One downside is that it pretends to be solid frame and not in I-beam profile. this may not matter in most cases, except when I want to use that void to run a pipe or so. 

I then tried something else. I used the original frame family and created that apex-filling with an in-place family of the structural framing category:

The advantage is that this can be used in arrays and it gives me the actual profile (except at the apex) in case I want to use that space for pipes. Disadvantage it looks like attached (joining doesn't work due to the profile of the frame family). i noticed that model-in place apex also duplicates in the family browser. I tried grouping the frame family and the apex family. but creating an array then also duplicates all the Apex in-place families. so, this may not be the most (computing resource) efficient option. 

SteveKStafford: yes, I'm probably in "overmodeling" and "deep into rabbit hole" territory. I think for this project I just leave it as I have it now. I just realized my single-slope frame for other parts of this project doesn't use a "I-beam" profile, it is just solid (like my in-place model). So, maybe that is just good enough for now. Next time I have a metal building project I will be better prepared. 

Sometimes I can't let go till I'm convinced i tried all options. Once I know what hard limits of Revit are, I can settle for the (less than perfect) solution. 

Thanks for all the help. If you have more suggestions, I may try a bit more. if nothing else, i now know more about Revit than when i stated this. 

[ToanDN · Accepted solution]

Copy or Array on a Plan view.  There are no restrictions or constraints whatsoever.  And it is a system component, not an in-place model.  One is top-shelf, the other belongs to the trash compactor.

[SteveKStafford]

In-place modeling fails big time as soon as you have to change the frame because each in-place family is unique. Making a group, adding the in-place family and copying the group doesn't resolve that either.

As soon as you've got more than one, in-place starts losing it's place in the should I do it equation.

[HVAC-Novice · Accepted solution]

I think I solved it, by using good old "searching for someone else's work and copy it". 

I found a few more families with the kinks. Some had unsuitable ways to describe the kink location. The attached one seemed to have the best parameter assignment. I changed the parameters to instant. 

I still don't totally understand what some of the parameters actually control. I wasn't able to find how some parameters actually control the geometry since I didn't see them in the views. but at this point, I just use it as is. 

And "Apex Haunch" probably isn't the right term. This refers to "kinks"