The new Philip GlassRobert Wilson collaboration, Monsters of Grace (BAM), is an important experiment in virtual theater. A computer-animated 70mm film visible only through 3-D glasses, Monsters is about perception itself. The very first scene appears to be desert, but as the background mountain range turns white and a bare foot slowly descends, it becomes beach. This transformation is mysterious, not banal, supported by the usual Glass-Wilson tropesrepetitive arpeggios, glacial pacing, and sets that seem more dramatic than the action unfolding in them. Finding magic in the ordinary is really the whole point. Spectators are constantly disoriented. One image appears to be a blurred ball of fuzz, but gradually becomes a sleeping polar bear suspended in the air a foot or two away; disembodied hands reach in to poke the fur. A few scenes like the Mondrian grid that turns from white to black left me cold. But I admit to being partial to whatever broke the fourth wall and hovered over the audience. A table set with chopsticks and empty bowls appeared to jut out to the row just ahead, then atomize, as if illustrating the scientific fact that solid objects are made up of invisible spinning particles. There was nothing to this scene, yet I could have watched it for quite a long time. A beautiful libretto based on the writings of Rumi, the 13th-century Sufi mystic and original whirling dervish, celebrates insubstantiality and invisible connection, i.e., spirituality and love. At this point in the new field of digital opera, however, the medium is definitely the message. Perhaps with the introduction of story, character, and more realistic looking "synthespians" (digital actors), it will become something more.