# Roof Components - Ridge Purlin

## Ridge purlin settings

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Using the dropdown list at the top of the dialog, you can select existing settings. The disk icon lets you save the current setting under the same name or a new name. Via the management icon you can create new settings, also by adopting existing settings, modify existing settings or delete them. See 'Save settings' in the 'General Help' manual.

**Identification number:** The identification number determines the purlin material. Use the button at the end of the field to open the database and select a material.

**Designation:** The designation simultaneously selects a specific purlin type. Depending on this purlin type, purlins can be positioned differently. Accordingly, some fields in the dialog change their meaning and labels. For example, the beveled purlin is positioned not by a fascia board but by the bevel width and a clearance.

**Width:** Width of the purlin.

**Height:** Height of the purlin. For the 'beveled ridge purlin' the height can be calculated based on the rafters. If you choose the option 'by rafters', the following fields are activated. There you can enter a rounding value and the cambium height for both sides.

**Rounding for height:** If the height of the ridge purlin is calculated from the rafters, you can enter a rounding value here. The calculated height will then be rounded up to the next full value set here. For example, a value of '0.02m' will always produce heights (cm): 10, 12, 14, 16, etc.

**Cambium height front side:** For the calculation 'by rafters' the program requires the cambium heights of the front and back sides of the ridge purlin.

**Cambium height rear side:** For the calculation 'by rafters' the program requires the cambium heights of the front and back sides of the ridge purlin.

**Level:** Level to whose top edge the fascia board refers. Usually this is level 0, where the rafters also lie.

**Fascia board type horizontal / vertical** or **Bevel width front side:** This field changes its meaning depending on the chosen purlin type. For beveled purlins you can enter the bevel width for the front roof plane here. For all other purlin types the fascia board type for the front roof plane is set here.

**Fascia board relative to level** or **Distance from top edge of level:** This field changes its meaning depending on the chosen purlin type. For beveled purlins you can enter the distance to the top edge of the selected level of the front roof plane here. For all other purlin types the fascia board matching the fascia board type is entered here.

**Fascia board type horizontal / vertical** or **Bevel width rear side:** This field changes its meaning depending on the chosen purlin type. For beveled purlins you can enter the bevel width for the rear roof plane here. For all other purlin types the fascia board type for the rear roof plane is set here.

**Fascia board relative to level** or **Distance from top edge of level rear side:** This field changes its meaning depending on the chosen purlin type. For beveled purlins you can enter the distance to the top edge of the selected level of the rear roof plane here. For all other purlin types the fascia board matching the fascia board type is entered here.

**Purlin direction:** With the 'purlin direction' option you indicate at which end of the purlin the start and end are located. For this, the roof plane is viewed from the eave. This information is important when writing member numbers at the start of members on the rafter-purlin plan and when you want to influence the position of the number.

**Connection rafter to purlin:** There are six settings in this field:

> **None:** No connection is created; both members simply pass through each other.
>
> **always notch:** The rafters always receive a notch when intersecting with this purlin, even if the rear edge of the purlin penetrates into the rafters.
>
> **always notch (consider panels in front of purlin):** The rafters also always receive a notch when intersecting with this purlin, even if the rear edge of the purlin penetrates into the rafters. In addition, the program searches for panels in front of the purlin. If panels in front of the purlin are found, the notch is enlarged by the panel thickness. The panels must be perpendicular to the global XoY plane and parallel to the front purlin surface. The panel must touch the front purlin surface and the top edge of the panel may end flush with or at most 20 mm below the purlin top edge. The panel may have been created in DICAM or in the wall.
>
> **possible cutout:** The rafters receive a notch when intersecting with this purlin as long as the rear edge of the purlin does not penetrate into the rafters. As soon as the rear edge of the purlin penetrates the rafters, a cutout in the rafter is created. The threshold 'Minimum cutout depth' is taken into account. As long as the cutout depth is less than the value set here, the cutout is not created. A notch still appears.
>
> **possible cutout (consider panels in front of purlin):** The rafters receive a notch when intersecting with this purlin as long as the rear edge of the purlin does not penetrate into the rafters. As soon as the rear edge of the purlin penetrates the rafters, a cutout in the rafter is created. The threshold 'Minimum cutout depth' is taken into account. As long as the cutout depth is less than the value set here, the cutout is not created. A notch still appears.\
> In addition, the program searches for panels in front of and behind the purlin. If panels in front of or behind the purlin are found, the notch is enlarged by the panel thickness. The panels must be perpendicular to the global XoY plane and parallel to the front purlin surface. The panel must touch the front or rear purlin surface and the top edge of the panel may end flush with or at most 20 mm below the purlin top edge. The panel may have been created in DICAM or in the wall.
>
> **Cut into purlin:** With this option no notch and no cutout is created in the rafter. Instead, the purlin receives a cutout (free cut).

**Rafter nail drilling**: A rafter nail drilling can be created in two ways. It can simply be information attached to the notch or it can be created as a separate drilling. Both options have different properties:

> **From notch**: The information for the rafter nail drilling is attached as information to the notch, is passed to the machine in this form and the machine treats the rafter nail drilling accordingly. This type of rafter nail drilling is not displayed in the structure. The diameter of this rafter nail drilling is set under 1-7-8 *Thresholds, machining* set.\
> This rafter nail drilling is created at notches and free notches.
>
> **Rafter nail drilling**: Below this group you can choose your own detailed setting. If one of these options is chosen, the rafter nail drilling is no longer created as information attached to the notch, but rather a separate drill hole is created and displayed as such. In addition, the rafter nail itself can also be generated.\
> This rafter nail drilling is created at notches, free notches (including ridge and valley rafters), at corner notches and cutouts (for very shallow rafters).

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**Connection purlin to purlin**: With this connection, purlins that meet under a ridge or valley rafter can be automatically connected to each other. Two connection types are available, each with several options. If both purlins meeting under the ridge or valley rafter have been assigned different connections, no connection is made.

> **Section**: For the 'section' connection there are two options. With 'continuous' each of the two purlins is simply cut off vertically. For a valley line the purlin is created so that its rear edge ends exactly at the valley line. For a ridge line the purlin is created so that its front edge ends at the ridge line. With the 'angle bisector' option both purlins are cut along the angle bisector.
>
> **End plate**: With the 'end plate' connection both purlins are joined with an end plate. The end plate can be created according to different criteria. The options of this connection let you determine which of the two purlins is to be relieved at the top.

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**Length at ridge line / valley line**: These fields determine the length of the purlin. The following rules apply for ridge lines and the same applies to valley lines:

> **Up to ridge line**: With this setting the ridge purlin is created as before; it ends at the ridge lines.
>
> **Up to rear edge of ridge rafter**: The program searches for the wider ridge rafter and extends the purlin so that it ends at the rear edge of that ridge rafter.
>
> **Ridge rafter - up to opposite roof plane**: The program searches for the roof plane intersected by the purlin axis. It then extends the purlin to the top of level 0 of that roof plane and cuts the purlin parallel to that level.
>
> **Valley rafter -- up to opposite roof plane**: The program also searches for the roof plane intersected by the valley rafter axis. It then extends the purlin to the underside of level 0 of that roof plane and cuts the purlin parallel to that level.
>
> Additionally, behind each of the two dropdown lists there is a field where you can enter a value. A positive value extends the purlin by that amount, a negative value shortens the purlin. For example, for a hipped roof situation you can have the purlin created up to the top of level 0 of the hip surface with a 2 cm clearance.

**Shortening at verge:** As soon as a purlin ends at the verge due to the input, it is shortened by the value entered here. Negative values result in an extension of the purlins.

**End machining at verge:** As soon as a purlin ends at a verge according to the input, the machining set here is attached to that purlin end. You can view and modify the parameters with which the selected machining is executed via the button at the right end of the field.

**Extension of the remaining purlin ends:** Purlin ends that do not lie on a verge can be extended (positive values) or shortened (negative values) using this setting.

After setting all values and options, you can enter the purlins using the following buttons:

**All ridge lines:** The configured ridge purlin is created on all ridge lines.

**Continuous:** The ridge purlin is created on the roof plane(s) that were graphically selected. If you select two opposite roof planes that border the same ridge line, the ridge purlin is created only once.

**Length-limited:** The length and position of the purlins can be specified by two points. The first point entered also determines the roof plane on which the purlin is to be created.
