It kinda makes sense for special effects artists to become movie directors. After all, so many movies these days are shot on sound stages in front of green screens. The artists presumably know more about what certain shots will look like in the computer, so they might as well be in control from the beginning. Of course, we've seen how bad some effects gurus can be at directing: Stefan Fangmeier (Eragon); Phil Tippett (Starship Troopers 2). It isn't a given, though, that they'll be bad. Joe Johnston is an example of someone who is capable of decent filmmaking (Jurassic Park III; Honey I Shrunk the Kids -- but also Jumanji) and a lot of us are optimistic about Colin and Greg Strause's work on the upcoming Aliens vs. Predator (aka AVP2).
The latest effects guy to make a go at directing is Rpin Suwannath (The Matrix Revolutions), who will be helming The Lotus Caves for Walden Media. Suwannath isn't completely new to the task. He has already directed green screen scenes for The Chronicles of Narnia: The Lion, The Witch and the Wardrobe and he's currently directing the third unit for its sequel, Prince Caspian. He also did some second unit stuff for Superman Returns. So, he's got some experience. But does that mean he needs to make the career change, especially when he's one of the highest regarded pre-visualization experts in his field? Well, hopefully he isn't abandoning his day job just yet, and surely he'll be applying his previs techniques to The Lotus Caves.
Suwannath's directorial debut will be based on the 1970s young adult novel by John Christopher and it will have to be very effects-heavy. Set on a moon colony in 2068, The Lotus Caves is a sci-fi thriller about two teens who break out of the airtight bubble lunar city to go exploring. While I'm not sure how easy it would be for rebellious teens to wander off a moon base and go for a joy ride in a moon buggy, some of the out-of-print novel's fans (writing on Amazon) make the story seem smarter and deeper than it sounds.