Use this macro to generate a distribution (spreading) of purlins in a selected area of the roof plane. Distributed elements include purlins and brace rods.
To begin defining the purlin distribution, open the Purlin distribution dialog from:
- Menu: Steel > Parametric structures > Purlin spreading
- Ribbon: ASD - Model > Parametric structures > Purlin spreading
- Toolbar Parametric structures > Purlin spreading
.
In the drawing area, click to specify:
- the beginning point of first purlin (P1)
- the end point of first purlin (P2)
- any point positioned on the last purlin (P3)
The 3 points (P1, P2, and P3) must define a plane unambiguously (they may not be collinear). Positions of these points determine the coordinate system (see the drawing below):
- Point P1 is the origin of the coordinate system
- Points P1 and P2 determine a direction of the X axis of the coordinate system
- Point P3 determines a direction of the Y axis of the coordinate system.
The Z axis of the purlin profile is always perpendicular to the roof plane.
After the distribution is generated, it is assumed that all purlins are parallel to each other and of the same length.
Use the options at the upper part of the Purlins tab to determine the location of distributed purlins with respect to defined points P1, P2, and P3 (purlin length and distances of the first and last purlins from the defined lines of purlin distribution).
Specify purlin parameters:
- Profiles
- Materials
- Families
Profiles available on the selection list are those defined in the Profile List dialog. To add a profile to the list, click 
. The Profile list dialog displays, where you can select a profile.
Families available on the selection list are those defined in the Family Manager dialog. To add a family to the list, click 
. The Family manager dialog displays, where you can select a family.
- Rotated - select this to change the setting of a purlin profile in the roof plane.
- In the edit field, specify a value of the shift (distance between the bottom plane of the lower flange of a purlin and the roof plane).