This dissertation proposes a form of environmental performance analysis for buildings called Making Information Modeling and Systems Ecology (MIMSY). MIMSY analysis combines aspects of exergy analysis and e[m]ergy analysis with making information modeling – a technique proposed for mapping and quantitatively measuring the flow of information across the design and construction of buildings. Making information modeling combines the concept of making grammars with graph theory and information theory to model designing and building as material computations. Graphs of making computations are used to trace the sources of information that influence building performance. A making information model shows the source and amount of information processed at each step of design and construction. Making information is shown to quantify economic use-value of decisions taken during design and construction in relation to stated performance objectives. The thermodynamic relationship between information and exergy is used to express making information as an exergy value. The exergy of making information is combined with exergy measures of other factors that contribute to the total use-value of a making process, such as the chemical and physical exergies of the materials and the exergy equivalent of the money exchanged for them. The ratio of the total exergy of a making process to its e[m]power (which measures the planetary-scale energy inputs to the process) is termed exformation. Exformation is proposed as a measure of the environmental performance of building relative to its use. Applying these concepts and techniques to a diverse range of hypothetical and real-world architectural projects demonstrates how environmental performance is related to various socio-economic issues.