Roof truss view in floor plan and 3D views don't match up

[wile e coyote genius]

Please accept my apologies if this is in the wrong forum as I was not sure where it should be. In the design of my building I had a need for a truss so I selected the "object" icon and selected the appropriate truss from the library. I placed the truss where needed. When it come time to cost out the truss I was asked to send a drawing of the truss with dimensions. Since I had never had to this before I didn't know how to create the drawing in AC but I could easily create it in my MCAD software. To that end I started to recreate the truss which is where I began to run into problems. If you look at the picture showing the 3D and floor plan views you will see that they don't align with each other leading me to wonder what the rectangular boxes shown in the floor plan actually represent. I made many dimensional checks on both views in AC and nothing lines up. It should also be noted that when in the 3D mode the truss is created as a single item which means that the only snap points are on the extremes of the item. There aren't any snaps where the web pieces meet the chords making measurements difficult in the 3D view. It's not possible to get dimensions from the floor plan view as nothing lines up with the 3D view. I am hoping that someone might be able to explain why the floor plan view and the 3D views don't correlate with each other and what do the square boxes in the floor plan view represent. Also, is there a way to add snap point at the ends of the web pieces?

Thanks in advance.

[mthd]

All the advantages of having an in house engineer hey ? Trusses and roof members do change when the plan does and so it needs to be kept up to date. We had our own truss and wall frame plant and my brother cut the framing timbers to size from the design software print outs. In our region they are usually prefabricated by the manufacturer who will supply a free no obligation quote before he gets the build and supply contract. Every truss has its own combination of gang plates and the software calculates it for you. I couldn’t be bothered taking the long route so I send my plans to the truss manufacturers. I would rather spend my time designing than obsessing over exact truss drawings. I let the computer do the work not me.

[Laszlo Nagy]

It is also possible to model Trusses using the Curtain Wall tool. You can even do it in a Section Viewpoint which is the natural choice for this type of geometry that is located in a vertical plane. Any pattern can be created, or Frames can be anywhere, Frames can have Profiles, intersection of Frames can be controlled, it will generate true 3D projection on the Floor Plan, and you can Label and Schedule individual Frames.

[Steve Jepson]

"All the advantages of having an in-house engineer hey? Trusses and roof members do change when the plan does and so it needs to be kept up to date."

Yes. I do all of my own pseudo-engineering and calculations before I send the Plans to the Engineer - even if the Plans need to have an engineer's stamp anyway.   There are a lot of things that are sized for the sake of constructability, availability, cost, builders' preference... rather than only for minimum strength.  I want all of those choices made before the Engineering is done in an effort to reduce his billable hours as much as possible.

No, the Plans do not change in any way that affects Engineering after I send them out to the truss manufacturer.

so they do not need to be parametric with the rest of the building.   More often than not, there is no reason to model any more trusses than might show up in a section or detail.   I do like to model trusses sometimes before the plans go to the truss manufacture for the sake of indicating the type of truss I want, heel heights, etc... 

"Engineered Wood Trusses - see Truss Profiles, Layout and Installations Details provided by the manufacture.", with some sort of truss showing in the Sections is usually sufficient.   Here, the Truss Plans are not required to be submitted with the Plans for Building Permits - so long as they are on-site at the first Framing Inspection.

However, I do like to get the truss plans as early as possible because I want my Calculations for beams, columns, and footings to match the manufactures truss reactions, and also to make sure of all the options I may want. 

[mthd]

Yes and the shape of the truss and the heal height and other details can affect our design. I recently had to specify the depth of a top chord, not to be less than a specific depth to allow a box gutter to be set down on a roof junction. I still leave the engineering to the manufacturer because that’s how we do things down this way. I have seen people in the USA use a program to design their own trusses as well.