A routine 4 a roof layout ?

Long time since I've been here.

Does anyone have a routine they may want to share which uses the
external walls of a building to generate a 2D roof layout with hips,
ridges and valleys. Some of the stuff I do confuses the hell out of me,
let alone the truss manufacturers.

What I've been doing is using an old, free "Home Architect" program to
draw a rough outline of the building and use that to generate the roof
layout. Works like a charm except for the fact it's a pain in the butt.
It doesn't export to DWG or DXF, just lets me see what the roof will
look like.

Thanks folks.

Bernard.

 

Ever tried the "topographic method" of offsetting polylines? It involves a
little calculation where the eave line breaks and roofs start at different
heights, but still works very well.

 

Find a new truss company. LOL. Every truss software program that I have
seen in the last 10 years has a layout program that analyzes and
calculates the planes of roofs to generate plan views of the roof
exactly as you spec'd, and if the truss company technicians cannot
generate roof lines from the info you supply it is only because they are
either too lazy, incompetent, or you have given them info that has
contradictory results (he says glancing down at an architectural roof
plan that is impossible as drawn.)

If you develop a strong working relationship with the truss company they
may even set up a copy of their software on your computer and include
you under their license (provided you pay for the extra seat)

 

You're going to let the truss guy design the roof?

After I throw myself in front of a bus, and have to spend a lot of time
convalescing, I've promised myself to do a cartoon of the same building
designed by each of the trades to suit themselves. From the forming guys to
the caulking guys. I think it would be a bit like that old cartoon of the
tire-swing....

 

It depends on the truss guy. Since I am a truss guy, I would feel better
about my designing the roof than the average architect (keyword is
average) or house designer.
The key to this working is the architect has to really know how he wants
the building to look and he has to have decent and accurate elevations
and sections.

I have a following of several architects who recognize that I usually
have a better ability to draw the plan view of their roof than they do
since that is my area of expertise. They send me 25%-50% completion sets
without any roof plans or with only some areas done and notes saying "I
don't know how to do this area. Figure it out. Send me a plan drawing
{without trusses) and maybe some 3d's to review and we can discuss it
and move from there."

I had another architect who drew a funky shaped building to fit on a
funky shaped lot and he drew impossible ridge lines. He also had the
floor designed to be supported by steel beams in the roof, but his floor
trusses could not span the necessary distances. I changed the 3 steel
beams from being hidden in the roof with angle iron tension bars
supporting a non-feasible floor to 1 steel beam in the floors,
recalculated his roof ridgelines with some back and forth discussions
and he was ready to go. Of course the field personnel screwed up the
funky angles, so I had to redraw it to work with the as-built walls.

 

You might have a point. I've seen the scenarios above, but consider them
evidence of inferior work by architects. An architect should have a 3d model
of the building in his head, and be able to draw it in 3d from any angle. I
don't fudge anything.

The most complex roof I ever designed, was built by a crew that not only got
it right, but was so proud of their work they gave guided tours to the ridge
during the topping off party. I was also pretty impressed by their
abilities.

I ended up using offset polylines to draw it in plan correctly. Not that big
a deal really. It takes more care than brains.