Roof Components - Rafter Input

The 'rafter input' function allows arbitrary rafters to be entered. This can be done as individual rafters at specific positions, but fields can also be subdivided. The program distinguishes three rafter types:

• Fixed rafter: The fixed rafter is entered as an individual rafter and is assigned the setting 'Yes (Fixed rafter)' in the input dialog box in the field 'consider as field boundary'. This causes it to be considered a field boundary when distributing field rafters. The fixed rafter remains at the initially chosen position. In the roof structure the fixed rafter is displayed in dark red.

• Field rafter: The field rafter is entered by subdividing a field and is displayed in "normal red." This rafter remembers the subdivision rule with which it was created. If a field boundary later shifts, the field rafters redistribute themselves automatically. If a field rafter is moved, it automatically becomes a fixed rafter and there are two possible reactions for the remaining field rafters:

  • The other subdivision rafters to its right and left redistribute automatically.

  • The two adjacent field rafters to the right and left of the moved rafter also become fixed rafters and the subdivision rules of the remaining field rafters are adjusted so that they remain at their previous positions.

• Additional rafter: The additional rafter is entered individually like a fixed rafter and is assigned the setting 'No (Additional rafter)' in the input dialog box in the field 'consider as field boundary'. Thus it is not considered a boundary when distributing field rafters; it is ignored as if it did not exist. This allows, for example, blind rafters to be entered. In the roof structure the additional rafter is shown in a light orange-red.

The following settings can be made for the rafters:

With the selection list at the top of the dialog box you can choose existing settings. Using the disk icon you can 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, or modify or delete existing settings. See 'Save settings' in the 'General Help' manual.

Identification number: The ID number determines the rafter material. Using the button at the end of the field you can branch into the database and select a material.

Member type / designation: Member type and designation are now determined as in other component inputs:

▪ There is no longer any restriction on member type.

▪ The default designation is adopted according to the member type but can be adjusted arbitrarily.

▪ If member type and designation are left empty, both will continue to be assigned automatically: Depending on the situation of the individual component, member type and designation for rafters, ridge members, valley members, etc. will be entered automatically.

Thus it is possible to label rafters used for specialized components accordingly, e.g. additional battens in the verge area, insulation strips. With an adjusted member type these components will not be considered rafters in certain situations:

▪ The component can be excluded as a support for the formwork. In the case of rafter-oriented it searches for at least 2 rafters as supports.

▪ The component can be excluded as a reference component for generating counter-battens:

Counter-battens are generated on rafters with the following member types:

- Rafters: 110-139, Counter-sills (Aufschieblinge): 170-179

- Filling timber 142: The length of the counter-batten is reduced to the length of the filling timber

- Ridge/valley rafters: 210-229, Counter-sills (Aufschieblinge): 270-279

Width: Width of the rafters.

Height: Height of the rafters.

Position: Layer in which the rafters are installed. The rafters lie with their top edge flush with the top edge of the layer.

Lowering from top of layer: The rafters can be lowered with this value. This dimension is measured from the top edge of the layer set above to the top edge of the rafters.

Positioning: With the positioning you specify which part of the rafter should be positioned:

Choice: With the "Choice" option you can, after selecting the point where the rafter is to be placed, graphically select the different positioning options. The program starts with one position; with the right mouse button you can select the next option and with the left mouse button you can accept the current position.

Left edge: The left edge of the rafter, as seen from the eave of the selected roof surface, is positioned.

Axis: The axis of the rafter is positioned.

Right edge: The right edge of the rafter, as seen from the eave of the selected roof surface, is positioned.

Shortening of the rafters: Rafters can be automatically shortened during input. The shortening can be applied to the upper and/or lower rafter end. If a rafter is shortened at the upper end, it automatically receives a perpendicular section. If it is shortened at the lower end, the set eave section is retained. This allows, for example, creation of a blind rafter (shortened at the bottom) or the lower rafter pieces for the layer of pitched-roof insulation.

If the option "top", "bottom" or "bottom and top" is selected here, the next appropriate fields are automatically enabled.

With the additional option "from profile" the rafter setting from the profile is adopted, while the other options (top, bottom, bottom and top) overwrite the settings from the profile.

Reference for shortening at top: So that the program knows up to where the rafters should be shortened at the upper end, you can select a reference line for the upper rafter end here.

A special case is the option "1st purlin top". With this option the program searches, starting from the upper end of the rafters, for the first purlin crossed by the rafters. First purlins are ignored. The rafters are cut at the first purlin found.

Distance for shortening at top: Additionally, a distance to the reference line for the shortening of the rafters can be entered here. A positive value shifts the cut line upward, a negative value downward.

Reference for shortening at bottom: So that the program knows up to where the rafters should be shortened at the lower end, you can select a reference line for the lower rafter end here.

A special case is the option "1st purlin bottom". With this option the program searches, starting from the lower end of the rafters, for the first purlin crossed by the rafters. First purlins are ignored. The rafters are cut at the first purlin found from below.

Distance for shortening at bottom: Additionally, a distance to the reference line for the shortening of the rafters can be entered here. A positive value shifts the cut line upward, a negative value downward.

Consider as field boundary: With this setting you can specify whether the rafter(s) should be considered as a field boundary. This affects the division of a field and the covering of the roof surface with the roof assistant. If a rafter should not be considered a field boundary, it will be ignored by the program during a division or when using the roof assistant, as if it did not exist. If it is to be considered, it will bound a field during manual division or division by the roof assistant.

Rafter nail hole: A rafter nail hole can be created in two ways. It can simply be an annotation at the notch or it can create a dedicated drill hole. Normally the rafter nail hole is set on the purlin and all rafters, hip rafters, and valley rafters that receive a notch from that purlin also receive this rafter nail hole. In some cases a single component should receive a different rafter nail hole. Then you can give that component its own setting. Both options have different properties:

From purlin: The rafter nail hole is taken from the purlin that creates the notch in the rafter. This can be a rafter nail hole created as information at the notch or an independent rafter nail hole, depending on the setting at the purlin.

Rafter nail hole: Below this group you can choose a custom, detailed setting that then applies only to this rafter and "overrides" the setting on the purlin. If one of these options is chosen, the rafter nail hole will no longer be generated as information at the notch but will become an independent hole that is represented as such. In addition, the rafter nail can also be generated.

Rafter at eave: For the connection of the rafters to an eave line various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

Formwork notch at the eave: A formwork notch can be generated at the 'eave end' of the rafter. The button at the right end of the field shows and allows you to change the values with which the formwork notch will be generated.

Rafters with an applied shortening are also considered in the calculation if they would terminate at an eave without shortening.

Rafters at the ridge: For the connection of the rafters to a ridge line various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

Rafters at the shed termination: For the connection of the rafters to a shed roof line various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

Formwork notch at the shed termination: A formwork notch can be generated at the upper end of the rafter when the rafter ends at a shed roof line. The button at the right end of the field shows and allows you to change the values with which the formwork notch will be generated.

Rafters at ridge purlin: For the connection of the rafters to a ridge purlin various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

Rafters at ridge/valley rafters: For the connection of the rafters to a ridge or valley line various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

Rafters at inclined rafters: For the connection of the rafters to an inclined rafter various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

Rafters at roof kink: For the connection of the rafters to a kink line various treatments can be selected. The button at the right end of the field shows and allows you to change the values with which the respective treatment will be generated.

After setting all values and options, rafters can be entered using the following controls:

Single rafter: Rafters are placed individually. You graphically select a point on the roof. The roof surface to which the rafter should belong is automatically determined by this point. After selecting the point, positioning is queried if you have set the positioning option to "Choice." Then you can enter a distance from the selected point to the configured positioning edge of the rafter.

This function generates fixed rafters or additional rafters depending on the setting.

Split 2 pts: With the "Split 2 pts" function any area between two points on a roof surface can be divided with rafters. To do this, use the mouse to select two points that bound the area to be divided. The first point simultaneously determines the roof surface to which the rafters should belong. After you determine the field, you enter the splitting function.

Divide field (field rafters): With the "Split field" function any field (= area between two rafters or roof skin lines) on a roof surface can be divided with rafters. To do this, click with the mouse into the area of the roof surface to be divided. The program automatically searches for the rafters that bound the area. On each side where no rafter is found, the outermost roof skin line is taken as the boundary. After you confirm the field found by the program (left mouse), you enter the splitting function.

This function always generates field rafters.