Evolutionary design is an approach that evolves populations of design variants through the iterative application of a set of computational procedures. For architecture and urban design, the developmental procedure typically needs to be capable of generating bounded variability, whereby design variants are both highly variable and highly constrained. This paper proposes a template for creating such developmental procedures. The template uses decision chain encoding techniques in order to generate a sparse skeleton model and then uses standard parametric modeling techniques in order to generate a detailed form model. A demonstration is presented where the template is used to create a developmental procedure for generating design variants for a large residential project.