topic Re: Truss Family Enhancements in Revit Structure Forum

Truss Family Enhancements

SeanSpence — Tue, 12 May 2015 12:49:16 GMT

The Truss Family is easy to use, but it lacks a bunch of features that structural engineers and designers need. Below are some enhancements that would make the family a lot more useful

More Web Member types.

Issue: When a truss is engineered it is almost always designed with more than one web member size. The members in the center are usually smaller than at the ends. The vertical web members are almost always different in size to the diagonal web members.

Suggestion: There needs to be an ability to create different sizes along the truss so that an economical design can be modeled easily. Currently there is only 1 web member size. 1 top chord size and 1 bottom chord size.

Currently the sizes of the individual web members can be changed once the truss is in the project. Unfortunately this is an instance only ability and does not reflect how trusses are used in building construction.

Truss Types.

Issue: Trusses are always defined as a type. There maybe 10 different types of trusses engineered with hundreds of those types used in a facility. Currently it seems the only way to create a type of truss with varying web members is to bring in a truss family, tab and select the individual web members and change the member size. The ability to change the size of individual web members is available once the truss family is in place but there is no way to have this change occur to the other types of trusses that are identical on the project. The current work around for this is to create a "Group" of the truss then copy it around to the different location where it will exist. While this approach gets the job done, using groups has several draw backs. Firstly using Groups in the numbers required to frame a building degrades the performance of the model substantially. Secondly once grouped beams and framing members attaching to the group no longer behave correctly, they dont attach as they would if the truss wasnt grouped. Thirdly groups seem to create export errors when using navis, the members dont always show with the correct family.

Suggestion: Allow custom changes to be saved to the family as a type rather than an instance change.

Truss Depth

Issue: Trusses are always detailed with a truss height defined. Currently when using the truss family template the top and bottom chords are located by there center of gravity/Center "y" location. Hence the height of the truss varies depending on the size of the top and bottom chord members See below

As you can see, there is a WT bottom chord and a Wide Flange Top chord. each has different depths, while the center to center of these members is 10'-0" the Out to out size is different.

The only way to fix this is to look up the different sizes of the top and bottom chord and subtract half of their depth from the truss depth. While this works it is not ideal. The truss depth has to vary from truss type to truss type depending on the sizes used. when chord sizes vary by small fractions of an inch, truss depths become in accurate.Out to Out of truss is what is important when modeling, not analytical location to analytical location.

Suggestion: Allow the graphical location of the element being used as a top or bottom chord be defined as top or bottom. Currently only the analytical location can be defined.

Truss Gusset Web Connections

Issue: Truss use gusset plates at the connection of the web members to the top and bottom chords of the truss. These gussets can become very big and create coordination conflicts with other diciplines who need to route utilities through the truss space. There is currently no way to add additional members to the truss family to model these accurately or to create a no fly zone collission element where the truss connection is. Because of this, any design over LOD300 cannot use the OTB truss family as part of the model.

Solution: Allow connection components to be inserted into the truss

Truss top and bottom connection

Issue: Projects that use trusses normally have a truss top chord plan and a truss bottom chord plan. This is because trusses are normally in excess of 8'-0" deep. Currently you can only connect members such as purlins and bottom chord bracing to the bearing chord selected in the truss instance properties. (see below)

If additional members need to be attached they need to be assigned to a different level. these elements dont connect to the truss and as such, their symbolic offsets dont work creating graphical representation errors on plan. Because they dont attach, they also do not move with the element if trusses move during the building designs evolution.

Solution: allow framing members to attach to both the top and bottom chord of a truss

Re: Truss Family Enhancements

SeanSpence — Thu, 20 Aug 2015 12:03:22 GMT

Truss z Offset Value

Trusses dont have the ability to have a z offset value like Beams and joists.

If a truss (as is normally the case) needs to be offset from the roof level so that a purlin can sit on top, then the Start level offset and end level offset need to be adjusted. This breaks the link with the level preventing purlins from automatically adjusting their graphicall end offset in plan and breaks the analytical model preventing alnalytical linking to analysis software.

Solution : Add a "z offset value" Similar to Joists and Beams (See below)

Truss - more options for member configuration

Anonymous — Mon, 05 Sep 2016 19:55:11 GMT

Trusses don't work well. There are not enough option to change the justification of the the memebers, rotate the members, change how the memebers connect to each other.

It would be nice to have horizontal trusses too. Trying to get three beams or more beams to join at a point is impossible to get it to look right with out unjoining the ends.

A space truss family would be great too.

Re: Truss

bosborne — Fri, 13 May 2016 12:04:41 GMT

Nested Shared Families inside of generic models work well for some of this, but you are right, trusses don't work well. If we could get adaptives to work/allow structural categories, it could pretty much replace the Truss category altogether...

Re: Truss

SeanSpence — Wed, 18 May 2016 21:57:13 GMT

See my post regarding this from the idea station that was migrated to this new revit Idea site.

http://forums.autodesk.com/t5/revit-ideas/truss-family-enhancements/idi-p/5631042

But I totally agree!

Re: Truss Family Enhancements

Anonymous — Thu, 19 May 2016 14:37:11 GMT

This is a much needed fix in Revit. Lots of time is spent trying to make trusses work in Revit in such a way that makes sence and helps the project move foward.

Re: Truss Family Enhancements

BDMackey — Thu, 19 May 2016 15:08:53 GMT

Agreed these are much needed updates. I would also like to see a more atuomated way to cope the members, I know this isn't always needed but ineveitably the question comes up and users are frustrated it is a one off thing

Re: Truss Family Enhancements

lionel.kai — Fri, 01 Jul 2016 21:12:51 GMT

The top and bottom chords CAN be adjusted to physical top and bottom, but again the problem (like the sizes) is that it's an INSTANCE (not a Type) change.

Re: Truss Family Enhancements

Discussion_Admin — Thu, 18 Aug 2016 20:28:55 GMT

Notice

This post was moved from an Idea station due to it having more than one Idea per submission for the team to consider as per the guidelines.

The original author has been notified of the move with a request to post the ideas individually.

Anyone who voted for this Idea is encouraged to return to the Idea board and vote on the new ides listed individually.

Thanks in advance for you understanding

Discussion_Admin

Re: Truss Family Enhancements

SeanSpence — Fri, 19 Aug 2016 11:58:54 GMT

YOU CANT BE SERIOUS!!!!

This was a front page top vote getter and you stripped it of all its votes and hid it from all that voted for it!

It was in the idea station before the current IDEAS page was even launched. That's where Autodesk support employees told us to put it!!!!

Re: Truss Family Enhancements

Discussion_Admin — Fri, 19 Aug 2016 12:45:44 GMT

@SeanSpence wrote:

YOU CANT BE SERIOUS!!!!

This was a front page top vote getter and you stripped it of all its votes and hid it from all that voted for it!

It was in the idea station before the current IDEAS page was even launched. That's where Autodesk support employees told us to put it!!!!

That is the correct place to post an Idea. But only one idea per post please as I stated in the PM I sent you prior to moving the idea to the general forum.

Such great ideas should have no issues getting votes reposed properly for the team and voters.

Thanks
Discussion_Admin

Re: Truss Family Enhancements

SeanSpence — Fri, 19 Aug 2016 13:12:43 GMT

If you previously voted for this and got a message stating that this had been move please like again. I apparently have to break it up into different ideas. once I get time to break it up I will re post here. Liking will give you a notification when I do this.

Sorry for the inconvenience.

Re: Truss Family Enhancements

chrisplyler — Fri, 19 Aug 2016 14:56:39 GMT

What? This is not more than one idea.

It's a single idea... IMPROVE TRUSS FUNCTIONALITY.

Re: Truss Family Enhancements

Anonymous — Fri, 19 Aug 2016 15:01:42 GMT

I agree. This is one single idea.

Also this is a REVIT STRUCTURAL issue.

Re: Truss Family Enhancements

Discussion_Admin — Fri, 19 Aug 2016 15:22:23 GMT

@41348 wrote:

I agree. This is one single idea.

Also this is a REVIT STRUCTURAL issue.

I agree that is the the functionality that the ideas here represent.

But there are several ideas here and they are MUCH more likely to get developed individually rather than in one post as it is better for the Devs.

did I mention it's much better for the devs to work on and justify one at a time .

Thanks I'll move it to the Structural board. We want it to get all of the correct exposure as possible

Thanks
Discussion_Admin

Re: Truss Family Enhancements

SeanSpence — Fri, 19 Aug 2016 17:09:57 GMT

Truss Family Enhancements have been broken up in order to enable developer workflows.

Please click and vote for each one below

Thanks

Sean

truss-family-enhancements-more-web-member-types

truss-family-enhancements-truss-types

truss-family-enhancements-truss-depth

truss-family-enhancements-truss-gusset-web-connections

truss-family-enhancements-truss-top-and-bottom-connection

truss-family-enhancements-z-offset-value

truss-family-enhancements-automatic-member-coping

Re: Truss Family Enhancements

chrisplyler — Mon, 22 Aug 2016 15:55:11 GMT

Discussion_Admin wrote:

But there are several ideas here and they are MUCH more likely to get developed individually rather than in one post as it is better for the Devs.

did I mention it's much better for the devs to work on and justify one at a time .

I get it, but it only gets done right if each dev is aware of and coordinated with efforts of others so that trusses end up functioning correctly as a whole.

If you get one guy working on the ability for types to remember a variety of different member sizes, and you get another guy working on gusset capability, and they don't know what the other is doing, you might end up with junk functionality as a whole that requires even more annoying work-arounds.

While I agree that the individual improvements can best be analyzed and implemented if they are presented as stand-alone requests...each item needs to be considered as part of the whole. The development of one item may necessarily impact the directions of development for each other item.

Re: Truss Family Enhancements

Discussion_Admin — Mon, 22 Aug 2016 16:11:11 GMT

@chrisplyler wrote:

Discussion_Admin wrote:

But there are several ideas here and they are MUCH more likely to get developed individually rather than in one post as it is better for the Devs.

did I mention it's much better for the devs to work on and justify one at a time .

I get it, but it only gets done right if each dev is aware of and coordinated with efforts of others so that trusses end up functioning correctly as a whole.

If you get one guy working on the ability for types to remember a variety of different member sizes, and you get another guy working on gusset capability, and they don't know what the other is doing, you might end up with junk functionality as a whole that requires even more annoying work-arounds.

While I agree that the individual improvements can best be analyzed and implemented if they are presented as stand-alone requests...each item needs to be considered as part of the whole. The development of one item may necessarily impact the directions of development for each other item.

The team requested the splits and Sean did an excellent job of re-posting these( kudos above!!) while trying them together so I think they can handle it ok.

Thanks for the feedback

Re: Truss Family Enhancements

SeanSpence — Mon, 22 Aug 2016 16:34:33 GMT

Thanks for getting behind this @chrisplyler. I was rather upset when I found that the original post had been moved.

But, I took a few deep breaths and reluctantly did what was requested. What is most important now is that the truss issue as a whole is being looked at and that we end up with a quality end result. Seems that Autodesk is now at least aware of it.

The best thing we can do is get as many of our work mates voting on these structural issues.

Thanks again! Really appreciate you having the ideas back.

Re: Truss - more options for member configuration - Status changed to: Under Review

haedicu — Mon, 05 Sep 2016 19:55:33 GMT

Thank you for this suggestion. We will be further evaluating this one in the near future and will keep you posted if we need any additional feedback or clarification. Please feel free to continue voting on this one as it will help us with the continued evaluation.

best regards

Udo