X15 Roof Trusses

[SNestor]

So, if you specify "roof trusses" in the structure tab of the roof build dialogue and specify zero inch heel height...the top chord of the truss sits at the outside edge of the wall main layer. 

 

Is this a bug...or, do we always have to specify a heel height when specifying trusses?

 

[SHCanada2]

I would think the onus is on us although setting a default is probably wise.

 

The truss above less the overhang is actually a legitimate truss on a gable wall 

[DavidJames]

Truss heel height is measured from the top of the plate, to the underside of the roof sheathing so the section drawing you provided looks correct

[SNestor]

Actually...if you look closely it's clipping the ceiling. So...something isn't working properly. I think I'm going to send in a report. 

[DavidJames]

I still think it's operating as it should. 

 

Unless I'm mistaken, the minimum heel height for trusses is 4"

 

 

 

[Kbird1]

7 minutes ago, DavidJames said:

I still think it's operating as it should. 

 

Your Image looks Correct , Steve's does not , the top chord is intersecting the Top plate causing a small sloped section against the wall too.

 

Steve are your Roof Planes the Correct Height?

 

M.

[DRAWZILLA]

1 hour ago, SNestor said:

Actually...if you look closely it's clipping the ceiling. So...something isn't working properly. I think I'm going to send in a report. 

yes i agree with you, something isn't correct with the truss specs. We never used to have to set the heel height for them, now we do.

[Garybills]

This was X14 

 

This is x15 with set to 0, it's lowering the raise off plate

X15 if you raise the Heel Height to 4 3/16"

 

 

[Kbird1]

Ok , looks like a bug for sure , though I'm not sure how this got by QS or Beta since Auto Trusses are a new Feature in X15,

so you'd think testing was scrupulous.

 

M.

[DRAWZILLA]

i thought this is a deliberate change because of a lot of complaints about the heal height settings. 

[Kbird1]

6 hours ago, DRAWZILLA said:

i thought this is a deliberate change because of a lot of complaints about the heal height settings. 

 

I don't know obviously, but as it is, if you choose Trusses now you will have to set the Raise + Hgt or Heel Height to the VSD of the Truss Member to get it correct, and I can see that being a problem especially for new Users  who don't know the ins and outs of Chief Roofs., and it seems to me it would be easy enough to program that functionality automatically since Chief knows the VSD.

 

M.

 

This Post of mine has more on VSD distances and a PDF here if anyone needs it....

 

https://chieftalk.chiefarchitect.com/topic/24689-vertical-structure-depth-vsd-rafter-table-pdf/?tab=comments#comment-198524

 

[SNestor]

Just FYI...I built the roof using "auto rebuild". I set the heel height to zero. You would think that the truss would build normally...with the bottom chord extending the outer surface of the main layer. 

 

The "auto truss" tool needs a lot of work to get me to use it on a regular basis.

[glennw]

I don't think it is a bug - more a not ideal default setting for the Heel Height.

Setting the Heel height to zero places the Baseline on top of plate and results in the ceiling being clipped.

Setting the Heel Height to the same as the Vertical Structure Depth places the Baseline at the traditional location so that the bottom chord is sitting on the plate and the bottom of the top chord sits on the outside of the main layer.

Setting the Heel Height to a value greater than the Vertical Structure Depth results in an energy heel.

If you always want your bottom chord to sit on the top of plate and underside of bottom chord to meet top of plate and outside main layer (ie, no energy heel), set the  Heel Height to match the Vertical Structure Depth in your Build Roof dbx default.

Maybe the default Heel Hight should be equal to the Vertical Structure Depth and not the random 300mm (in metric) it is now.

Only takes a second to change it in your defaults if thats what you always want it to be. 

 

Heel Height set to zero:

 

 

 

Heel Height set to equal Vertical Structure Depth:

 

 

 

Heel Height set to a value greater than Vertical Structure Depth:

 

[someguy]

I think truss manufacturers use the same callout on their trusses. It’s a tough one as the height varies with roof pitch and top chord depth. But using 4” would be close enough. 

[SNestor]

I understand that we can set the heel height to the vertical structure depth...but, why for sake do we have to? There is no one that would build a truss where the top chord intersects the outer surface of the main layer. I mean it's just dumb.

 

How does having to set this dimension help any of us get our work done quicker or more accurately?  And...how do new users know that if they don't want a raised heel that they need to minimally enter the vertical structure depth as the heel height? Crazy...

 

Chief engineers need to start over and fix this tool...my two cents.

[Kbird1]

2 minutes ago, SNestor said:

I understand that we can set the heel height to the vertical structure depth...but, why for sake do we have to? There is no one that would build a truss where the top chord intersects the outer surface of the main layer. I mean it's just dumb.

 

How does having to set this dimension help any of us get our work done quicker or more accurately?  And...how do new users know that if they don't want a raised heel that they need to minimally enter the vertical structure depth as the heel height? Crazy...

 

Chief engineers need to start over and fix this tool...my two cents.

 

I agree, while it may not be a BUG, ( in some people's eyes), I think it is definitely Bad or un-intentioned Functionality, that the Average User , especially those who don't visit the Forum will be calling TS about, and needs to be Fixed.....

 

M.

[CAmichael240114]

A  Standard Truss:

A standard truss has no heal height.

The bottom of the bottom chord sits on the top of the top plate and extends out to the wall framing exterior face where it intersects with the top chord.

The top chord under side sits on the bottom chord where the bottom chord meets the wall framing exterior face.

The truss heal height or energy heal height is the height from the top of the top plate to the top of the top chord vertically above the wall framing exterior face.

An energy heal serves two main purposes, one to increase the distance between the top an bottom chords to increase the structural span of a truss, the other to provide a greater depth between the bottom chord and the under side of the roof for increased insulation depth for higher insulation R-values.

 

[Chrisb222]

On 5/6/2023 at 10:36 AM, SNestor said:

So, if you specify "roof trusses" in the structure tab of the roof build dialogue and specify zero inch heel height...the top chord of the truss sits at the outside edge of the wall main layer. 

 

That seems normal to me. I would expect a zero heel height setting to do exactly that, although I can't imagine why one would want such a thing.

 

On 5/6/2023 at 10:36 AM, SNestor said:

Is this a bug...or, do we always have to specify a heel height when specifying trusses?

 

What I find odd is that when I open a new Residential Template, and do nothing but go directly to the Build Roof Dialog and click on "Trusses" it dumps in a 30" heel?? Also cannot imagine why that would be the system default. Is it just me or do others see this also?

 

 

IMO the default should be that the heel matches the VSD out of the box, but it can easily be programmed into your template. This is a test template saved as such, opened and go directly to the Build Roof DBX:

 

 

 

[JLU_Design]

In my area this is how truss manufactures define heel height.

 

 

 Chief defines heel height the same way in my experience.

To me the way Chief defines heel height makes sense but it could be that other geographic areas define heel height differently.

In my area heel height is the height difference between the top wall plate and the top of the roof structure at the outside of the wall framing.

If the heel height is set to 0 then you'll get this:

[Alaskan_Son]

3 hours ago, Chrisb222 said:

Also cannot imagine why that would be the system default. Is it just me or do others see this also?

 

Auto populates with 12" for me.  My guess is that it has something to do with the template you're using and how it may have been modified in the past. I believe that setting just remembers the last value you typed in there.

[Alaskan_Son]

21 hours ago, SNestor said:

I understand that we can set the heel height to the vertical structure depth...but, why for sake do we have to? There is no one that would build a truss where the top chord intersects the outer surface of the main layer. I mean it's just dumb.

 

How does having to set this dimension help any of us get our work done quicker or more accurately?  And...how do new users know that if they don't want a raised heel that they need to minimally enter the vertical structure depth as the heel height? Crazy...

 

Chief engineers need to start over and fix this tool...my two cents.

 

It sounds to me like you want a setting to auto calculate for a variable heel based on the Vertical Structure Depth of the Top Chord to mimic the old behavior.  If so, I think you'll have to send in a request for that.  I think that's a capability we simply lost with the introduction of the new heel height control.  It's not something I personally need, but I get it. 

[GeneDavis]

Show me a truss plant's drawing that has heel height shown differently than top plate up to intersect of top chord line.

 

I like the new setup.  Saves time.  Before, needed to do the math to get an energy heel roof height done correctly, now it's "auto."  Don't we all love "auto?"

[SNestor]

Yes...it's a computer program that knows the VSD when you set the top chord parameter in your defaults. I think the software should default to this as the heel height...and allow us to change it as needed. But - alas, I may be in the minority. 

[SHCanada2]

20 minutes ago, GeneDavis said:

I like the new setup.  Saves time.  Before, needed to do the math to get an energy heel roof height done correctly, now it's "auto."

 

I as well, pretty much all buildings up here have an energy heel, so to me the VSD is a value I would rareley use. The exception might be for a garage to ge the minimum height. 

But based on the screenshot above it shows the VSD, so one can just put that number in the heel hieght.

 

 it would be nice if it warned or did something if the specified heel height was less than the VSD.

 

[Alaskan_Son]

10 minutes ago, SHCanada2 said:

But based on the screenshot above it shows the VSD, so one can just put that number in the heel hieght.

 

This would seem to be the logical solution on the surface, but there's a bit more to it than that.  Most notably, the VSD would change with any changes to the pitch of any given roof plane.  In particular, this would become a big problem wherever roof pitches were being controlled independently using Wall Directives. 

 

The current system is set up to handle either a static heel height OR a variable (Automatic) Birdsmouth.  What I think Steve would need to solve his probelm is an Automatic Heel Height checkbox.