Since 2003, VAPO has provided vulnerability assessors with state of the art modeling and simulation capabilities. ARA employees possess the varied and unique skillsets necessary to develop a production ready software application backed by decades of blast, structure, and vulnerability research. VAPO combines an immersive 3-D view of the assessment site so that users can model realistic scenes that are convincing to their customers. VAPO relies on a calculation engine that predicts the effects of a terrorist threat including air blast, fragmentation, cratering, structural damage, equipment damage, glazing damage, and human injury statistics. VAPO provides results in 3D, HTML, and 2-D plot formats to convey information to decision makers.