Techniques for representing criteria for blueprints as computer-readable expressions, and evaluating blueprints based on computer-storable (or readable) expressions are disclosed. A computer-storable expression can be constructed based on one or more functions, parameters and operators stored in respective libraries. A dynamic blueprint-evaluator can interactively evaluate a blueprint as the blueprint is generated (e.g., drawn) and/or altered. The dynamic blueprint-evaluator evaluates computer-storable expressions that represent various criteria for the blueprint and can indicate when a criterion has not been meet (e.g., highlight a plan or a drawing). The dynamic blueprint-evaluator can be implemented as or as a part of software used to generated blueprints (e.g., CAD), thereby allowing blueprints to be automatically and dynamically evaluated using a computer.