# Roof Structure - Copy Components

The "Copy Components" function allows copying roof structure components. They can be copied onto the same roof surface or onto another roof surface. The following component types can be copied:

* Sills, intermediate purlins
* Ridge purlins
* Rising purlins
* Rafters
* Inclined rafters
* Hip rafters
* Valley rafters

Only one component can be copied at a time, because combining multiple components may lead to unpredictable situations.

The procedure varies slightly depending on the component type, since different points must be selected.

Special considerations for purlins:

* For continuous purlins, essentially only the target roof surface is requested and then the purlin is created with its original input values.
* For length-limited purlins, the start point and end point are requested. This allows the purlin length to be modified. However, using right-click with the mouse you can adopt the original length.

Special considerations for rafters:

* Fixed rafters are also created as fixed rafters at the target position. If this places them within a field of field rafters, two fields are automatically created and redistributed automatically.
* If you copy a field rafter, either a fixed rafter or a field rafter that distributes itself automatically will be created at the target position.

If a copied component has manual edits, those edits are copied as well. The new component thus appears exactly like the original component. Because the new component also adapts automatically to the new situation, conflicts with manual components can occur. In such a case the result may differ from that of the copied component.
