We present a novel means of algorithmically describing a growth process that is an extension of Lindenmayer’s Map L-systems. This growth process relies upon a set of rewrite rules, a map axiom and a novel geometrical interpreter which is integrated with a 3D simulated environment. The outcome of the growth process is a digital surface in 3D space which has “grown” within and in response to its environment. We have developed a complementary Evolutionary Algorithm (EA) that is able to take over the task of generating the rewrite rules set for a growth process. Using a quantitative multi-objective fitness function that evaluates a variety surface properties, the integrated system (EA + Growth Process) can explore and generate diverse and interesting surfaces with a resemblance of organic form. The algorithms have been implemented to create a design tool for architects called Genr8.