Eric Swain and Troy Bernier are two South Florida scientists who are inspired by their love of sci-fi. But after leaving the lab, they don’t just go to midnight movies—they make their own. The results are low-budget, campy crowd pleasers that resemble recent cult hits like “The Room” and “Birdemic” much more than “Star Wars” or “Star Trek.” Brooklyn Underground Film Festival co-founders Myles Kane and Josh Koury followed the filmmakers for more than two years, shooting over 200 hours of footage, during the production of their most ambitious project to date. The experience is captured in “Journey to Planet X,”a feature-length documentary that will have its world premiere at the Tribeca Film Festival on April 21. I spoke with Swain and Bernier about their devotion to science fiction, finally casting actors instead of friends and co-workers, and how making movies for fun on weekends led to a trip to Tribeca.