Strategy to model existing metal building

[HVAC-Novice]

We have  a large metal building and I design lighting and HVAC upgrade. I don't do any structural work, but still want to represent the building relatively accurately. That way I and contractor know where the structural elements are to avoid. Below is a typical section showing girts and purlins. I think I'm fine modeling the main frames with oob families. But the girts and purlins may be time-consuming, so I look for an efficient way.  

My initial idea for the wall is to use a stacked wall and only model the metal cladding to leave space for the girts. For the girts I was wondering if some beam system or other automatics way is better, or if I just place them manually. There are many bays, but I can just pretend to use a very long girt. I'm not quite sure how to handle the batten insulation. It kind of will be in the way of things, bit isn't an obstacle like structural elements. Below the stacked wall i created:

for the roof I could leave the roof as tick as it is since the purlins sit under the roof. I don't know if beam systems, or using structural floors or something would work better. 

I'll try some things. but if someone has done that before and can give some hints on what would be efficient to do, that would be great. 

[syman2000]

You can create wall sweep profile and load into the project

In the wall type, you can add sweeps and start adding the profile.

When you add that to stack wall, it will become part of the wall

[barthbradley]

Parts.  

[barthbradley]

https://help.autodesk.com/view/RVT/2023/ENU/?guid=GUID-DA150C6B-996C-4C70-9E8C-3C536C232851

[HVAC-Novice]

Thanks all. I realized different walls have different girt spacing. So, unless i create a new wall type for each wall, it seems using the profiles won't work. 

I think I understand where the parts idea is going... but how would the exact framing be defined in the wall layers (like the 3.5" wood in the example)? For me any wall material will turn into a a homogenous mass (not studs). Or is that some curtain wall system? anyway, that would suffer the same issue, that I can't freely change the girt height for different walls. 

I looked into using Z-strutural framing family to manually place on the wall. but i fail at the point that the center of the girt will be in the wall, not one face. So it is half sticking outside. 

I also wonder if it is better to set the main-frames and attach girts to that (like in real life). Maybe that is more how a structural model would be built. 

[syman2000]

You can create curtainwall and use the girt as mullion so you can adjust the girt height manually.

[barthbradley]

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@HVAC-Novice wrote:

Thanks all. I realized different walls have different girt spacing. So, unless i create a new wall type for each wall, it seems using the profiles won't work. 

I think I understand where the parts idea is going... but how would the exact framing be defined in the wall layers (like the 3.5" wood in the example)?

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Not clear what you are asking. You wouldn't define the individual girts in the Basic Wall assembly. You would have only the girt layer and thickness defined. The individual girts would be done as curtain walls or beam systems, as I showed above.  In lieu of Parts, you could model the walls in parts from the get go. That is, you would create a separate Wall Type for each layer and then sandwich them together - pretty much the way in will be constructed in the field.  The Wall Type for the girts would be done with a Curtain Wall Type or Beam System.  

...btw: my stud layer is more than "wood". It's also batt insulation, blocking, etc.  

😉

[HVAC-Novice]

Sorry for the late reply. I wasn't ghosting you guys, I just had to bid out a different project. I made some progress:

I placed Z-girts on the exterior of the frames and on grid lines.

2 issues: you can't change the plane or grid line you place them on after the fact. So you really need to know beforehand what to do. The other issue is that the split-element tool only partially works. I need that for the overhead doors and only could split at some locations. I read this is a new feature in R2024.1. Alternatively I can place multiple girts. I was able to split one of the purlins, but only in one specific location. I tried in 3D view, and section. it is like the split tool can't select the girt. 

This trouble makes me think I should try one of the methods you mentioned above. 

For the roof purlins I placed the C-purlin in a beam system and used the roof as a plane. this went surprisingly well. I still have to correct the exact extends of the system and clean up the edges. I picked lines in 3D, and probably should have used a roof view. the purlins probably aren't exactly placed, but this should be good enough for my purpose. 

I also edited some frames and need some help. the building has a center column. But I decided to use a single-span frame and place the center column separately. This way the family is more flexible. but here is my issue: this frame has what I call an "Apex Haunch" where the top has the thicker and flat part (hightlighted). This likely is the wrong terminology, though. 

i tried to edit the profile to adjust that. But when I edit the sweep, I can't really tell what plane or parameter actually determines the peak height. The "Rise" parameter controls it, but I don't see what it actually controls. Red line determines what i need to change it to. But i don't know how. Does anyone have any ideas? I'm sorry, i really have no experience with such sweeps. There seems to be a "section Shape" parameter, which I assume is a hard-coded structural parameter. 

[HVAC-Novice]

After my above method of of manually adding girts, I tried your method of adding Zee-profiles as sweeps. I probably should have that rights away. Because that seems more practical with doors etc. I think it is less hassle to create multiple walls with different girt heights than what I did with physical girts. Good enough for my purposes. 

I actually didn't do a stacked wall this time and manually added the walls since i feared i will have to create multiple stacked walls in addition to multiple walls with girts. 

It didn't look like roofs can have sweeps, so for the roof it looks like the beam system is the best option. 

I think I'm mainly good with Metal building modeling (good enough for HVAC and Lighting projects....). Except that "Apex Haunch" still bugs me since that could be in the way of something.