(NBC NEWS) -- 3D movies such as "Avatar" and "Alice in Wonderland" have proven to be such a hit with audiences that Hollywood is racing to make more of them.
More than half a dozen 3D films have opened so far this year and a dozen more are slated by year's end.
But more 3D films also means more competition, not only for dollars but also for theaters to show them.
"Not every screen in this country can show films in 3D and beyond that, it's about market saturation," notes Hollywood.com box office analyst Paul Dergarabedian. "Do people get burned out on it? Is it too much 3D?"
In fact, 3D films have seen their opening week box office numbers decline as a percentage of their overall ticket sales.
"Avatar" set the standard with 71 percent of its tickets for the 3D version, but more recently "Toy Story 3" saw 60 percent, "The Last Airbender" 56 percent and another box office hit "Despicable Me" sold just 45 percent of its tickets in 3D.
"That may mean audiences are being careful about spending that extra cash on 3D tickets," says Dergarabedian.
It's a factor studios have to consider when they convert films not originally shot in 3D, such as "Clash of The Titans", into the format.
Director Jon Favreau told a Comic-Con audience last weekend he's ditched plans to film his Sci-fi western "Cowboys and Aliens" in 3D.
"Take the money you save and see it twice," he told fans.
Either way, Hollywood will gladly accept moviegoers' money whether its for 3D films or not.