The pricey motion-capture epic Beowulf may not be blowing up the box office 300-style, but it’s a sensation in 3-D: So far, the 84 IMAX screens where it’s unspooled using the revamped technology account for a fifth of its $57 million gross. And according to Paramount distribution chief Rob Moore, Beowulf‘s first-weekend gross could have been up to 40 percent higher had the film been released entirely in 3-D, instead of only on the 788 screens locations where digital 3-D projection is now available. These numbers are likely to encourage theater owners to speed up their 3-D rollouts — and they’ll need to get on it fast, because by 2009, event films including James Cameron’s Avatar and DreamWorks Animation’s Monsters vs. Aliens will be presented in the resurgent format. As for Beowulf, Paramount hopes its box office numbers hold steady with patrons continuing to pour into those 3-D-equipped theaters. But there are challenges: It’s not exactly family-friendly, and there’s a little movie called I Am Legend on the way that’s likely to eviscerate everything in its path, 3-D or not.