Phenomenological simulation of efflorescence in brick constructions

Abstract

In human constructions, repetitive patterns can be handled by different texturing methods. However, almost all techniques do not consider weathering phenomena, missing a very important visual effect for realistic rendering. Among a great number of weathering effects occurring on constructions - in particular on fired-clay brick walls - efflorescence implies important visual changes and their removal (surface cleaning) is an economic problem in numerous countries. Due to the complexity of the physics involved, we propose in this paper an original phenomenological simulation of this weathering process on fired-clay bricks. In this case, efflorescence is materialized by a thin white powdery deposit of water-soluble salts on the surface or in the pores of masonry. We propose a method to generate the texture of efflorescence-affected fired-clay brick. First, we synthesize a brick solid texture from digital photographs using a classical solid texturing technique. Then, we add efflorescence by a phenomenological algorithm representing salt transport and crystallization in porous building materials for each brick separately. We can build aged walls by changing the parameters of efflorescence for each brick.