This is the crucial "first weekend" in the US for Antz, from the DreamWorks studio, and What Dreams May Come, starring Robin Williams. The audiences on these days determine whether films fly or flop.
Interest in these two latest heavily hyped movies has been heightened by the fact that recent big-budget films which used computers to the limit, such as Godzilla, have been less than successful. The trouble may be that nowadays, if you can imagine something, you can get the computer to reproduce it. But a computer can't tell you if the plot's any good.
"The guy sitting in front of a screen is like the director," said William Sargent, joint chief executive of FrameStore, based in Soho, London. "He decides what props go where, when things happen. The fact that you can do that is because the technology has developed; in fact, it has caught up with people's skills. But people are becoming more ambitious in what they aim to do."
It doesn't necessarily make them realistic. The many films this summer about asteroids threatening Earth didn't bother noting that in space, explosions are silent. It was attention to that sort of detail which explains why Stanley Kubrick's 1968 masterpiece 2001: A Space Odyssey is still held up as an example of what can be done with a strong imagination and good models.
Stuart Robertson of POP Film said: "So many movies get produced as 'now see the world's largest computer generated [effect]' that it really has a tendency to destroy suspension of disbelief. I think that's a real danger."
Moreover, the effects aren't always effective. Insiders in the business can easily spot badly done computer-generated images (CGI). But they also acknowledge that the more human something is, the more easily we recognise that it's fake. "Machines are a doddle, but we're nowhere near to creating realistic faces," said one.
That shouldn't be a problem for Antz, which cost $75m and is only the second full-length film to be made completely by computer animation.
The story is simple enough: Z is an ant (voiced by Woody Allen) who overcomes his neurosis about being "the middle child in a family of five million" and impresses the beautiful princess ant as he saves his colony from an evil soldier ant.
But the comedy is aimed at adults, and the question is whether adults will want to see a CGI film, or whether they'll think it's for children. Thus it's an important few days for Jeffrey Katzenberg, the studio chief of DreamWorks.
What Dreams May Come uses CGI more conventionally: early reviews have praised it and its effects. Stuart Robertson calls it "a daring movie" that "tries to overwhelm people with beautiful environments".
Sargent is confident that it will, and that the demand for computer graphics will continue to rise. "I don't think anybody felt the quality of the CGI in Godzilla was bad," he said. "It was just a bad plot."Reuse content