Roof Trusses

[Beaglemommy]

After about 4 days of figuring out how to model trusses, I can sleep now. My ultimate goal: model a fully parametric truss where the overhangs are different slopes from the main part of the truss. I wanted to be able to place it like a beam with out it automatically connecting itself to centers of bearing walls, enter in the slopes, and adjust the overhangs. See image, "Goal picture".

I've seen posts where ppl edit a wall profile (which I thought was a genius workaround, but not a good solution for me at this time) but most people just can't seem to get trusses to work well. I know others of you may have better or different successes than what I've done. But I wanted to share my discovery incase it's helpful to anyone.

I tried to re-create trusses with truss family templates (overhangs didn't come out well).
I tried to fake it with beam-based family templates (the span edges of the trusses would embed itsself into the wall centerline & the bottom of the trusses would not line up with the reference planes that I wanted)
After hours of re-creation...I used a line-based family template. I don't know why I didn't think of it before. You can see what I've done for a simplified truss in the images. I still have to put in vertical and diagonal webs - but that's a breeze once the chords are in.

[Craig_L]

It would be awesome if, once you complete the truss family, you share your family to save the rest of us the terrible brain bleeding involved when creating truss families...

Nice one!

[Beaglemommy]

It would be awesome if, once you complete the truss family, you share your family to save the rest of us the terrible brain bleeding involved when creating truss families...

Nice one!

Thanks! These are a few of them that I have, I haven't put in the webs, but at least this can get you started. I just didn't want to forget to post them. My apologies for it not being totally complete.

CT=Common Truss
HT=Hip Truss
JT=Jack Truss
OT=Overframing Truss

[jayfunkEIT]

...to save the rest of us the terrible brain bleeding involved when creating truss families...

Nice one!

I am very new to Revit Structure and roof trusses make me want to jump off a bridge right now!!

[Craig_L]

I am very new to Revit Structure and roof trusses make me want to jump off a bridge right now!!

I recommend planning it out on paper before you jump in to the screen. Work out what you need to constrain first, and what paramaters you will need. It's pretty frustrating but once you can build some you'll see how powerful it is and how much time it can save you...
Just have something handy to deal with the nose bleeds when your brain hemorrhages

[jayfunkEIT]

I recommend planning it out on paper before you jump in to the screen. Work out what you need to constrain first, and what paramaters you will need.

I just think there should be an easier way to model trusses in REVIT. I need to come up with a gambrel style wood roof truss for the main building with top chord overhangs and it's making me want to consider a new career, lol. I also tried making a simple W truss for a dormer that comes off the main roof and I couldn't even get that to work with my roof and girders. This project also calls for some valley trusses, I have no idea how I'm going to do that either. These are pretty common type conditions in the wood framed projects we do around here and I'm very disappointed there is not an easier way to model different roof trusses.

I tried using the Attach/Detach top chord command and building a new truss family... someone please shoot me now!

[mbalsom]

Here's a couple I made years ago, I use them every now and then in section detail, have a look and see what you think.

[Richard at AA]

Here is a hip roof system family I have been playing with - still working out some minor bugs and have not fully tested it...but thought I would share anyway.

I grew tired of making special hip trusses, jacks and flat top-hip trusses, etc and got something useable (attached).

Parametric properties (all instance properties) include:
- Roof Span
- Roof Pitch
- Overhang
- Girder Setback distance
- Top Chord Depth
- Hip Truss Ply Quantity
- Girder Truss Ply Quantity

Known Issues: I had some issues getting a working formula that would automatically display a center jack truss when needed - right now there is just a flag I use until I figure that out. I have not fully tested the truss spacing, but it seemed to work the couple times I set that to other than 24" - though some formulas assume 24" o.c. spacing at the moment.

Any tips to improve it would be appreciated! Eventually, I would like to make it possible to set a different pitch on all three sides.

Not evident from the jpegs are the visibility parameters that hide the trusses not used. Again, any tips to improve it in any way, free free to reply.