Flatten Plan view of a ROOF

[marc2M]

Hello,

I am trying to make shop drawings a roof for a residential project. I am trying to figure out how to get a flattened 2d plan view of a sloped roof. The current 2d view is inaccurate as it shows the horizontal projection of the roof and not the actual length of the roof if laid down horizontally on the ground.

The reason I am trying to do this is so that I can create a 2d shop drawing of the roof and rafters. Since this is an advanced BIM software it should be easier compared to manually  drawing the plan in AutoCAD. Any help is appreciated

A27:5001 USA 

[mthd]

Hi @marc2M, As you know normally a roof plan would be drawn in 2D with the projection only. The cross section would show the length of the actual rafters on the incline. So if you measured your rafters with the measure tool, you would get a measurement to be able to know how to represent your rafters in plan view to show the actual span instead of the just the projected length. This is not usual in my region so you would have to notify the shop workers that you have the actual rafter lengths depicted in plan.

[Karl Ottenstein · Accepted solution]

Hi @marc2M ,

As @mthd noted, typical roof plans are 2D projections - augmented by section/elevation views; it is rare to need flat views of components other than in cases of SIP manufacture etc in which case the SIP manufacturer typically uses their specialized software to generate the drawings that the factory floor machines will use.

You can sort of get what you want, though.  The easiest thing to produce would be dimensionable flat views of each roof plane - obtained by viewing the roof in 3D, then using the "look to perpendicular of clicked surface" button in the "3D Visualization" toolbar (turn it on if its off) ... same command in the View > 3D Navigation Extras menu ... and finally, create a 3D document from that view.  The 3D document will let you dimension as you describe.

If you need an exploded view of each roof plane ... each plane would still have to be a separate 3D document ... there isn't an easy way of doing that if you've modeled with the roof tool as a single roof assembly (with corresponding cutting body).  You'd have to right click the roof and do a "split into single plane roofs", after which you can select individual roof planes for 'show selection in 3D', do the view perpendicular thing and capture a 3D document... then each document would have a single plane for you to dimension.

Of course, here I've assumed a top view of each roof plane.  The bottom view would be different because of thickness, intersection angles, etc... but you can rotate the model in 3D and view the bottom view of each plane the same way.

Maybe that will get what you need?

[jl_lt]

I agree with @Karl Ottenstein and @mthd that its not common for roof plans, as that information is extracted from section along with plan, otherwise, you can run into a lot of measurement troubles on-site if not made perfectly clear to the contractor.    Otherwise, the method described by @Karl Ottenstein might be just what you need. 

[marc2M]

@jl_lt , @Karl Ottenstein , @mthd. Thank you guys for your responses. I agree with the work around to get the result I want. And you are right that the SIP manufacturers have specialized software for production drawings. I was thinking since ArchiCAD is a fairly advance software, maybe it had some tools to get a similar result. I am in fact trying to create shop drawings for a prefab roof similar to SIP. I guess i will use the 3d views method and have to manually draft the drawings.

[marc2M]

Hello @Karl Ottenstein , the method you described about creating a 3d document is theoretically correct. But unfortunately, it does not work in practice. When ArchiCAD creates a 3d document it is not to scale and the 3d object like roof, although looks correct, is completely off scale and is much smaller. 

[Karl Ottenstein · Accepted solution]

My 3D documents respond 100% to whatever scale they're set at.  Only the roof plane that you did a 'look to' will be to scale... but your dimension text and the printable size of the drawing respond to the scale setting for the 3D Document / View and should be accurate.  Check the scale saved with your view and/or the scale being used when you open the 3D document viewpoint... or if you over-rode the scale in a layout or in a print dialog to 'fit to page' or something like that.