My model, which was able to generate shadows from multipatchs quite nicely, is broken by Service Pack 4. I traced it to the Skyline tool, which requires the Use Refraction (optional) box to be checked to create volumetric shadows. With the installation of SP4 this is greyed out and only trace lines are able to be created.
Luckily SP4 can be uninstalled, however even after this I am having trouble running shadow creation against a multipatch selection, although the sample data works, the same model run against my multipatch features creates a shadow for every object in the dataset (instead of just the one selected). I have another model which uses extruded data as it's input, as this creates a multipatch from the selection it is unaffected.
What's the story ESRI???