This technical sketch describes how a standard analysis technique known as modal decomposition can be used for real-time modeling of viscoelastic deformation. While most prior work on interactive deformation has relied on geometrically simple models and advantageously selected material parameters to achieve interactive speeds, the approach described here has two qualities that we belive should be required of a real-time deformation method: the simulation cost is decoupled from both the model's geometric complexity and from stiffness of the material's parameters. Additionally, the simulation may be advanced at arbitrarily large time-steps without introducing objectionable errors such as artificial damping.