Forums >> Community >> Newbies >> creating box section truss system

SGotthard

active

Joined: Tue, May 10, 2011
6 Posts
No Rating

Hi,

I am in need of creating a kind of box section truss system, but I am new to revit and I'm problems manipulating the trusses to create what I want. (I'll attach a sketchup-export which shows what I am after!)

I've tried loading truss familys and then (sketchup-style) duplicate and rotate, which didnt work.

I've also tried creating a new family, but there's simply too many question that pop up. (For example how to i create a truss in which the inside members keep generating as I pull the truss to become longer) Also it seems like that tool only works in 2D, so to speak, as I can only create a top and bottom member.

Anybody got some hints on how to work with this?

Hope I'm making it somewhat clear what I'm after. English is not native to me and it gets tricky describing my problems with all these terms.

Thanks!

// Simon

Attached Images

This user is offline

mbsteve

active

Joined: Fri, Sep 22, 2006
759 Posts

If this truss is repeating, as your sketch up model indicates, make a generic model of it. Then import and array. 

Attached Images

This user is offline

itsmyalterego

active

Joined: Thu, May 28, 2009
829 Posts

For being new to revit you're able to articulate yourself well and take on ambitious things.  Scalable trusses, true parametric families that add more trusswork as you lengthen it are very complicated to get to work right. I avoid it still since in-place families are more efficient timewise for most of our projects.  

I think, you mean, like mbsteve is saying, that you want the trusses to duplicate?  or do you really mean stretch?  Are there going to be any connecting members between the boxes?  Because that would be more hard. 

SO, assuming you only need to build one box, which is repeating; from what I can see there are only THREE separate faces that need to be drawn, the copied, rotated, moved, etc.  yay.    From my experience, sweeps are the easiest form to manipulate.   Just draw a sweep with a very short path, and a complicated profile.   Finish thess three, then jump around between elevations and floor plans to rotate and move them into position.

This user is offline

SGotthard

active

Joined: Tue, May 10, 2011
6 Posts
No Rating

thanks for replying!

however, i can't work out the box section part, or maybe i don't understand what you mean.

the pic you sent me seemed to be your average "2D truss", which has been arrayed. in my case i would need two trusses next to each other and then one on the top and one on the bottom, in between them, to join them and hence create a box section truss system. don't know how to do it though.

This user is offline

SGotthard

active

Joined: Tue, May 10, 2011
6 Posts
No Rating

itsmyalterego,

thanks!

i tried to explain the box section thing in the earlier post, didn't see your post before i posted it.

i'm not sure what you mean. don't know what a sweep is (might have to look that up!)

however, creating three separe faces, rotating them and joining them to create this system, that's what i don't know how to do.

maybe that's what you are trying to explain, but i'm not sure i understand the complexity in what i wwant to do! :D i figured you could basically import trusses, manipulate and rotate and fit them (sort of like in sketchup). 

This user is offline

itsmyalterego

active

Joined: Thu, May 28, 2009
829 Posts

This is a rush job since I'm at work   but this is what I'd suggest you do for building an in-place box truss that you can copy/array as you wish.   Like I said, as three different panels you copy/move/rotate to build your box, here's an example of a couple faces selected. 

Attached Images

This user is offline

itsmyalterego

active

Joined: Thu, May 28, 2009
829 Posts

Ahh - no.  importing families will likely be too much of a burden.  Sweeps, extrusions, revolves -- these are some of revits built-in modeling tools. 

Extrusions might sound like they make the most sense, but they're a little more finicky than sweeps in a couple ways.  Sweeps are extrusions, where you draw the path, but they're a little more free from constraints and easy to work with. 

If you go to the home tab --> Component --> Model in place, you can start your own family, using these tools. 

This user is offline

SGotthard

active

Joined: Tue, May 10, 2011
6 Posts
No Rating

thank you very much for your help and for taking the time out of your work!

still a bit confused, but i'll try and read through what you wrote a couple of times and really dig in to the sweep-thing!

thanks again and take care

This user is offline

itsmyalterego

active

Joined: Thu, May 28, 2009
829 Posts

Okay, well, the basic thing you need to take out of this is that you can make your own "in place" families, families that you don't need to load into the project.  It's very nice, because you can build exactly what you want, the downside is that families your build in place are less flashy and "smart" than most you'll find available for download. 

But when you have something like your box beam, odds are very good that nobody has modeled something like it before, and so making it yourself is your only option. 

In every-day work, I do a lot of modeling.  Custom family-building.  So the modeling tools are pretty handy to get good at.  And since you know sketchup, it should be a pretty easy thing to get into.  There should be lots of Threads on this forum about "Model In-Place" and such.  Don't confuse it with "conceptual mass" though--that's for more complicated organic forms.  good luck!

This user is offline

mbsteve

active

Joined: Fri, Sep 22, 2006
759 Posts

I agree with itsmyalterego an inplace family is just fine for the 3D trusses you are trying to create. To be technically correct your vertices should line up across from each other. Plan the layout of the trusses carefully.

This user is offline

Truss steel system family creation

3

need help making delta truss system or space truss ???

0

Revit 2012 Truss System (framing members not showing)

4

Truss - Rotating

2

Section box in Section??

13