AutoCAD Architecture General Discussion

AutoCAD Architecture General Discussion

Posts: 5
Registered: ‎11-15-2001
Message 1 of 3 (53 Views)

Modifying Roof Slabs

53 Views, 2 Replies
08-23-2007 05:41 PM
When creating roof slabs, I'm given the option of inputting the elevation of the roof slab. I'm assuming that means the plate height. I also notice in the properties dialog box that it asks for a few other dimensions which to me seams useless. Can the roof slab be created to show a standard roof rafter configuration (see attached drawing)? I've reviewed a few publications to find, but to no avail. Hopefully, someone out there can help me with this problem.

Thanks, Glen
Distinguished Contributor
Posts: 551
Registered: ‎11-01-2003
Message 2 of 3 (52 Views)

Re: Modifying Roof Slabs

08-24-2007 03:31 AM in reply to: alcornnw
Your best answer is VisionRez which is an add on to ACA. They have various options and although an extra cost it is more than offset by its abilities. It is an imperial programme but if you are metric I believe that it can still be helpful but you would have to ask them for details. (I think their site is
While it is possible to model rafters in ACA it is time consuming.
A lot depends on the level of detail and accuracy you require. I do not believe that roof slabs understand bird`s mouthing but it may be possible to set the slab thickness so that the baseline would pass through the point of the seat cut and the tail would be formed by the oversail.

A lot of people moan about additional cost but I believe that ACA can waste your time like no other programme.
Maybe the clever people will chime in and prove me wrong.......

New Member
Posts: 1
Registered: ‎08-24-2007
Message 3 of 3 (53 Views)

Re: Modifying Roof Slabs

08-24-2007 09:38 AM in reply to: alcornnw
I agree, and am curious for an answer on this too. Attached is a drawing that anyone but ADT programmers could draw a roof from. I've been trying to get my head into this too, but the cryptic B and C dimensions in Properties for roof slabs seems insane! Who draws this way? Nobody I've ever met.

Should just be options for thickness, pitch, plate ht., overhang, and critically - if the roof slab (rafter) starts at the inside face of the wall, outside face, or an offset dimension (horizontal).

I can make no sense of what Autdesk has done here and it's infuriating to waste time trying to understand it their nonsense when it could have been so simple.
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