Boundary conditions on the fire layer

[Kareem Illahi]

Hi Emanuele, 

I see the page on the wiki it is still under TODO but I was wondering if it is currently possible to edit the fire layer boundary conditions?

For example, if I have a polygon in the shape of a rectangle could I have 3 sides of the rectangle be the extent of the burned area and the 4th side be the fire line.

Thanks

Kareem