A modal synthesis package has been developed for jMax. The whole set of bodies and interactions of the Modalys synthesizer have been rewritten. The package allows a new aproach to the synthesis techniques known from Modalys providing real-time interaction. It extends the existing set of synthesis classes in jMax with the possibilities of physical modelling. A virtual instrument is built form individual jMax objects representing bodies and interactions linked by named variables. An additional object implements the modal synthesis loop as a single jMax signal processing routine respecting the sample by sample constraint compelled by the physical system.