1. Researcher, Dept. of Graphical Expression, Univ. of Extremadura, Avda de las Letras s/n, 10004 Cáceres, Spain (corresponding author).
2. Professor, Dept. of Graphical Expression, Univ. of Extremadura, Avda de Elvas s/n, 06006 Badajoz, Spain.
3. Full Professor, Dept. of Architectural Constructions II, Univ. of Seville, Avda Reina Mercedes 4, 41012 Seville, Spain.