With the "Heal Selection Filter" in "Gimp", I could create a continuous shingle roof needed for texturing the fractured roof parts:
"Cell Fracturing" done:
kenanproffitt As far as I've understood it, it's not necessary to change the setting to "Random" in the "Recursions" section of the "Cell Fracture Addon", if the number of "Recursions" is set to "0". It only determines which parts are choosen for the next level of breaking up the pieces (only the smaller or the bigger ones or by "blindly" picking the pieces).
The "Material Indices" for setting a "Rim Material" start with "0" so that if the "Rim Material" is the second one in our "Material Stack" the setting should be "1". Higher indices than the material with the highest index obviously just select this last mentioned material.
