# Free Roof Area - Input Functions

## 3 Points

The position and orientation of the roof surface are defined by three points.

If the '3 points' option is selected in the drop-down list, the three points must be chosen after closing the dialog box. This can be done either in the XoY view or in any other view. After a point is selected, the coordinates of that point are displayed in a dialog box.

There is a button in the 'Z coordinate' field. If this is selected, the dialog box is hidden and a point can be chosen to determine the Z coordinate. After the point is chosen, the value is displayed in the dialog box.\
If the 'Ok' button is selected, the next point must be chosen. After the third point is confirmed, the roof surface is generated. Afterwards, the next roof contour polygon can be selected.

## Profile

A profile defines the roof pitch. In addition, a reference line as the building edge must be selected. Alternatively to the reference line, the rafter direction can be determined with any line and the position of the theoretical building edge can be set with a point. The eaves overhang of the profile is disregarded and the eave height from the profile is adjusted accordingly.

If the 'Profile' option is selected in the drop-down list, a reference line for the profile must be chosen after closing the dialog box. The fall direction of the rafters is then perpendicular to this reference line. Alternatively, a line for the rafter direction and a point for positioning the profile (building contour) can be chosen.\
A small dialog box with two buttons is displayed to choose between the input alternatives.

If the 'Reference line as building edge for the profile' button is chosen, a line must then be selected. This line then corresponds, for positioning the profile, to the building contour line of a normal roof determination. The view is rotated to the XoY view to select the line.\
If the line lies on the boundary of the roof contour polygon, the roof surface rises toward the center of the polygon.\
If the line lies inside or outside the polygon, two rise directions are possible. To determine the rise direction, a red arrow is displayed in the XoY plane. This arrow indicates the rising direction of the roof surface. If the initially displayed direction is rejected twice, a different line can be selected as the reference line for the profile.

If the 'Rafter direction and point for the building edge' button is chosen, a line must first be selected. This only indicates the rafter direction and therefore can be chosen at any location. After the line is confirmed, a point for the position of the building edge must be selected. For this purpose, a line is drawn with the mouse that is perpendicular to the line indicating the rafter direction. The point positions the building edge for the profile. The building edge is always perpendicular to the line that indicates the rafter direction.

The same applies to the direction of the roof surface as described above.

## Roof pitch + 2 points

If the 'Roof pitch + 2P.' option is selected in the drop-down list, two points must be chosen after closing the dialog box. This can be done in any view. After selecting each point, the coordinates of the point are displayed in a dialog box. The same dialog box as used for the '3 points' input is used here.\
After entering the second point, it must be checked whether it is possible to position a surface with the specified pitch through these two points. If two valid points are selected, the rise direction of the roof surface must still be determined. For this, the procedure described for input via a profile is followed.\
Only if a line through the two points already has the roof surface pitch relative to the XoY plane will the rise direction no longer be requested.

## Roof pitch + 1 point

If the 'Roof pitch + 1P.' option is selected in the drop-down list, after closing the dialog box an additional point must be chosen and the rafter or eave direction and the rise direction must be determined. The point determines the vertical position of the roof surface. After the point is selected, which can be done in any view, the display is rotated to the XoY view.

After choosing the point, the coordinates of the point are displayed in a dialog box. The same dialog box as used for the '3 points' input is used here.\
After the point is confirmed, a line must be chosen. The line can indicate the rafter direction or the eave direction. A dialog box with two buttons is displayed to select this.

After the rafter direction or the eave direction has been determined, the rise direction of the roof surface must still be specified. For this, the procedure described for input via a profile is followed.

## Referenced roof surface

This function allows the pitch, orientation and vertical position of an existing roof surface to be adopted and transferred to another roof contour line.

If the 'referenced RF' option is selected in the drop-down list, an existing roof surface must be selected after closing the dialog box. Once the selection of the roof surface is complete, another roof contour polygon can be chosen. The roof surfaces are generated independently of each other. This applies even if the two roof surfaces overlap or one roof surface lies entirely within the other.\
The roof surfaces are not merged or intersected.

## arbitrary points

If the 'arbitrary points' option is selected, any number of points can be chosen, but at least three points must be selected.\
When the selection of points is complete, it is checked whether the points lie in a single plane. If the points are coplanar, the roof surface is generated. If the points are not coplanar, a notification appears and the option to place the roof surface approximately centered among the selected points is provided. If an 'approximated roof surface' is to be generated, it lies in a plane for which all chosen points have the smallest possible distance.
