Page 877 - Chief Architect Reference Manual

Drawing Trusses

If you intend to use roof trusses, you need “Roof and ceiling surfaces too close together
first to build your roof planes with this in or cannot be found, so cannot make truss.”
mind. Before building the roof, select the The incorrect truss may still display in floor
Trusses (no Birdsmouth) checkbox in the plan view with a label of the form “TR-*”. If
Build Roof dialog. When this is checked, it does, it should be deleted or moved. See
roof plane thickness is based on the default “Editing Trusses” on page 879.
Top Chord Depth set in the Framing
Defaults dialog. See “Trusses Panel” on page One or both ends of a truss may be truncated
855. if they are drawn across another truss. If this
happens, it will end exactly on the surface of
If Trusses (no Birdsmouth) is not checked, the existing truss, producing a girder truss.
the roof plane thickness is determined by the See “Girder Trusses” on page 891.
rafter Depth setting on the ROOF panel of the
Framing Defaults dialog. If you plan to use Trusses can end on interior walls. You can
both trusses and rafters, you should leave this draw a truss that partially crosses the
unchecked. building by starting and/or ending it within
24” (600mm) of an interior wall. The truss
Roof Truss Placement extends over the wall’s Main Layer. Its end
lines up with the Main Layer surface on the
A roof truss can only exist in a space defined far side of the wall.
by the roof planes above it and the ceiling or

manually drawn Ceiling Plane below it. Roof Truss Webbing
This is because the shape of a truss is defined The webbing in a newly drawn truss is
by the location of the roof and the ceiling.
controlled by the Top Chord and Bottom
If the program either does not find both roof Chord settings in the Framing Defaults
and ceiling planes, or if there is not enough dialog. See “Trusses Panel” on page 855.
room between them to model a truss, a Changing these default values may cause
warning message displays. For example, if different truss configurations such as
you draw a truss in a roof overhang where kingpost, queenpost, fink, double fink, fan,
there is no ceiling, this message displays:
howe, or double howe to be represented.

Drawing Trusses

Trusses cannot be generated automatically: To draw and replicate trusses
the must be manually drawn and then 1. Select the either the Floor/Ceiling
replicated. All trusses are drawn similar to
the way CAD lines are and can be drawn in Truss or Roof Truss t o o l , t h e n
floor plan view only. See “Draw Line” on click and drag within either a floor/ceil-
page 296. ing platform or one or more roof planes.

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