Curved Parametric Truss

[funkman]

Sheeeesh, what have I gotten myself into?! Just when I think I am getting on top of this project, my big mouth opens and I "inadvertently" say to the client that I can create a curved truss that extends beyond the second floor building envelope (building approx 10m wide = 30 ft) and is fixed to the ground a level below. Then the buidler I was with said it wouldn't cost any extra over his original price. The Clients eyes went googled-eyed and he agreed that would look great!!!

Then the reality sets in. What did I just say??? I am only a beginner and wouldnt have the first clue to begin this. I have searched the forums but could not find anything - would anyone have a family that I may use? In such a hurry he said he needs the drawings updated for early next week.

Could anyone help?
Thanks muchly,

[beegee]

Firstly, heres a link (www.rugi.org/tipsandtricks/RevitTutorial/index.htm) to an excellant chewt on creating parametric trusses from our old friends at RUGI.

And secondly, this link will take you to some of RUGI's timber trusses (www.rugi.org/cgi-bin/woodtrussesexch.pl). You can change them to steel of course. There's a bowsting there that may be useful.

[funkman]

thanks beegee, I am not really confident in creating these type of families but will jump in and give it a go.

[funkman]

ok, so I have tried to create the family in accordance with the "choot", please see attached. Problem is the truss web members are protruding beyond the chord, and when it is tested, it doesnt drag as per the example, Perhaps this is because of the curved nature of the truss and the radius dimension that i have constrained.

Also, do I have to create a new truss for different lengths, or is there are way to add or delete web members automatically if the overall length reduces or increases?

Any help?

[gnl]

I tried the truss out and it seems like its just a matter of setting the correct values ffor your parameters... it does stretch correctly but you have to change the radius parameters for the geometry to be correct along with the length...

as for the members protruding out of the chord, I would suggest you create a void constrained to the chord and cut the member sweep with it so they will not display like they do now. The reson they now protrude is of course a geometrical problem....

In order to get more web members in your truss you would have to get into arrays... and probably I would suggest using nested families...
if you have time its a lot of fun!

ciao

[brantf]

my advice to you would be to creat a truss that isn't parametric. unless you will be changing the shape and size of the building or using the truss in multiple projects then the time you put into making a working truss will never pay off. Just work out the sizes of your truss and use the appropriate massing tools to create just one truss and throw 'er in there. Well thats my two bits hope it'll save you a little grief.

[gregcashen]

Agreed. If you ever need one again, then make a parametric family...otherwise, create an in place family for this jobby.

[David Conant]

You may find that creating it as a real family works better even if there are no geometric parameters. You can still add comments, type marks, etc. Schedule and tag will work more reliably, and you can use it as the basis for other families later.