A software shell for assisting in VLSI package design is discussed. Called packaging design support environment (PDSE), the shell integrates tools for modeling and simulation of electrical characteristics of VLSI packages. Parameter extractors tools calculate inductance and capacitance for multiconductor, multidielectric, two-dimensional structures with loss dielectrics. The simulation tools compute pulse response characteristics of uniform, multiple, coupled, and lossless transmission lines. The PDSE shell provides facilities for supporting the package design cycle. Such support facilities include an interface to couple PDSE with a CAD design database, model and simulation experiment libraries, simulation management procedures that guide evaluation of alternative design models, and data analysis support tools. Expert systems techniques are being incorporated into PDSE.