# Log Construction Implementation - Purlin Penetration

## General

The studs in the wall can be interrupted by purlins (component type 300 to 329). This situation is called purlin penetration. Only purlins whose axis lies parallel to the global XoY plane are considered. The purlin must fully penetrate the wall. Purlins that do not penetrate the wall at a right angle are treated separately.\
It is possible that modifications may also be generated in the purlin.

## Shape of the opening

The opening around the purlin can be created so that it is open at the top (U-shape) or closed all around.\
If the option 'Opening open at top' in the drop-down list is set to 'Yes', the opening around the purlin is extended up to the top face of the wall. All studs above the purlin are then separated in this area.\
If the option 'No' is selected here, the opening around the purlin is closed on all four sides.

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## Size of the opening

The values in the fields 'Top', 'Bottom' and 'Side' in the section 'Clearance between wall and purlin' determine the size of the opening. The purlin can also be tapered in the area of the wall. However, the size of the opening in the wall always refers to the raw member of the purlin. The depth of tapering in the purlin is not considered.

## Tapering in the purlin

Tapering can be created in the purlin in the area of the wall. If the purlin is not perpendicular to the wall, tapering is created in the purlin only on the top and bottom faces.\
The values in the fields 'Top', 'Bottom' and 'Side' in the section 'Tapering in the purlin' determine the depth of the tapering.

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The length of the tapering is additionally influenced by the value 'Recess depth of the purlin'. If the value is greater than zero, the length of the tapering decreases. If the value is less than zero, the tapering becomes longer.

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## Modifications in the wall

If a stud contacts the side face of the opening along its entire height, the stud receives a cut-off section.\
If a stud does not contact the side face of the opening along its entire height, a taper, a free leaf or a notch is created in the stud.

{width="3.165277777777778in" height="1.1041666666666667in"}

If the value in the field 'Recess depth of the purlin' is greater than zero, an additional modification is generated in the studs of the wall. This additional modification is only created when the purlin meets the wall at a right angle.

For studs that meet the side face of the opening along their entire height, an end plate is created on both sides of the stud (D and F). The depth of the end plate results from the value in the field 'Recess depth of the purlin' plus the value from the field 'Side'.

For studs that do not meet the side face of the opening along their entire height, an open recess is created on both sides of the stud (D and F). The depth of the open recess is determined in the same way as for the end plate.

## The input fields

**Opening open at top**: This sets whether the purlin opening should be extended up to the top face of the wall or not. See also Shape of the opening.

**Clearance between purlin and wall - Top**: The value specifies the distance between the top of the purlin and the upper edge of the opening.\
If the value is negative, the studs of the wall penetrate the purlin.

**Bottom**: The value specifies the distance between the bottom of the purlin and the lower edge of the opening. If the value is negative, the studs of the wall penetrate the purlin.

**Side**: The value specifies the distance between the purlin and the lateral edges of the opening. If the value is negative, the studs of the wall penetrate the purlin.

**Tapering in the purlin - Top**: The value specifies the depth of the tapering on the top side (E) of the purlin.

**Bottom**: The value specifies the depth of the tapering on the bottom side (C) of the purlin.

**Side**: The value specifies the depth of the tapering on the sides (D, F) of the purlin.

**Recess depth of the purlin**: The value indicates how far the purlin penetrates the wall with its full cross-section. See also: Tapering in the purlin.
