The overcrowding of Comic-Con in San Diego is starting to have a positive effect on San Francisco sister event WonderCon, with the latter becoming more attractive to the entertainment biz as an alternative venue to promote their projects.

This weekend’s event, kicking off Friday, will feature first looks at tentpoles like Warner Bros.’ “Green Lantern,” Universal and DreamWorks’ “Cowboys and Aliens” and Relativity’s “Immortals”; TV shows like Fox’s “Terra Nova” and BBC America’s “Doctor Who”; and vidgames like Activision’s new “Spider-Man” title, to name a few.

Making the trek to meet with attendees will be cast members, creators and producers including Ryan Reynolds, Jon Favreau, Blake Lively, Peter Sarsgaard, Paul Bettany, Nathan Fillion, Roberto Orci, Logan Lerman, Joe Wright, Mark Verheiden, Scott Stewart, Kellan Lutz and new Superman Henry Cavill.

WonderCon has long been a more intimate affair than Comic-Con, attracting about 39,500 to one of the halls of San Francisco’s Moscone Center. In comparison, Comic-Con drew 126,000 attendees in July to San Diego’s overflowing convention center. WonderCon’s largest ballroom, which hosts the film panels, seats 3,500 compared to the 6,500 that fill Hall H in San Diego. This year marks WonderCon’s 25th anniversary and the 10th installment for Comic-Con Intl., which acquired the event when it was hosted at Oakland’s smaller convention center.

“It’s not a regional show any longer,” said David Glanzer, director of marketing and public relations for Comic-Con Intl. “It’s a national show. We like to call it the comic industry’s biggest little secret. It’s intimate enough where people have a good time but attracts superstar guests.”

Because of the sheer number of fans that studios can reach at one time, San Diego Comic-Con has turned into a key platform through which Hollywood can launch buzz-building campaigns around upcoming movies, TV shows, games and other entertainment properties.

But with so many projects heading down the coast each year, it’s getting harder for projects to stand out and get noticed.

At the same time, with so many tentpoles on the sked in May or June, films need to produce panels a year before their release, often leaving filmmakers with little to show in terms of footage.

WonderCon’s April berth on the calendar is enabling marketers to deal with some of that scheduling.

For example, “Green Lantern’s” extensive visual effects forced WB to hold off on showing some of the DC Comics adaptation’s key scenes until its Friday panel, which will include star Ryan Reynolds. Pic bows June 17.

Hindered by its own production demands, Relativity couldn’t reveal too much of its warring Greek gods pic “Immortals,” helmed by Tarsem Singh, until WonderCon. Its own panel will be the first fan fest of any kind that its star, Cavill, has attended since landing the lead in WB’s “Superman: Man of Steel.”

“WonderCon is perfect for movies coming out in the summer,” said Peter Adee, president of theatrical marketing and distribution at Relativity. But Relativity saw WonderCon as an opportunity “to get to the early fans and show them what ‘Immortals’ was all about so that they embrace us” once the film comes out Nov. 11.

Having Hollywood lift WonderCon’s profile and pair up traditional film and TV show programming with a large comicbook offering was always part of the plan.

“One of the things we tried to do when we took over WonderCon was let people know that we’re the same family behind Comic-Con,” Glanzer said. “That really paid off.”

WonderCon boasted the cast of Paramount’s “Star Trek” reboot. Christian Bale and Tobey Maguire felt more comfortable talking to fans of Batman and Spider-Man at the more intimate confab. Jerry Bruckheimer also made the trip with Jake Gyllenhaal to promote Disney’s “Prince of Persia: The Sands of Time.”

“We have a long history of being able to deliver audiences, speak their language and deliver what they want to see,” Glanzer said. “We put on the types of shows we would want to attend.”

Glanzer stresses that less than 25% of the programming at Comic-Con is made up of hyping upcoming Hollywood projects.

Studios just do a “better job at promoting their presence and getting a lion’s share of the press,” Glanzer said.

Other projects set to present at WonderCon include:

• Films “Hanna,” from Focus Features; Summit Entertainment’s “The Three Musketeers”; Screen Gems’ “Priest”; and indie comedy “Super.”

• TV shows “Falling Skies,” the alien-invasion series from TNT and DreamWorks TV that’s produced by Steven Spielberg and premieres in June; “ThunderCats,” the series Warner Bros. Animation is prepping for Cartoon Network this fall; Fox’s “Breaking In,” starring Christian Slater; and “Human Target,” the latter based on the DC Comics property. All will unveil footage for the first time, while the CW and Warner Bros. TV will screen a full upcoming episode of “Nikita.” The new season of “Doctor Who” includes an episode penned by Neil Gaiman, who will be on hand to discuss his involvement with the show.

• “Green Lantern: Emerald Knights,” Warner Bros.’ direct-to-homevid animated movie that the studio will release June 7.

WonderCon’s tech-savvy attendees are just as eager to spread word of mouth via Twitter and Facebook as those at Comic-Con — perhaps even more so given that many come from nearby Silicon Valley.

Hollywood’s increased presence at the show is paying off for WonderCon’s organizers.

Ticket sales are going up. After filling up the Marriott Marquis for the first time, a second hotel, the InterContinental, was added and is also nearly at capacity.

And while San Diego is working with Comic-Con to expand its convention center and is offering up local hotel meeting space to keep the confab in town, WonderCon has room to grow in its current home. Two more halls are available at the Moscone Center.

Adee calls the WonderCon crowd the “Alpha dogs of media consumption.”

“Those are the people that are absolutely on the front lines of what’s hot in movies, fandom — they are the type of people we want to adopt us early on,” he said. “Everyone is trying to reach that audience. You can never start too early.”

“It’s important to share but don’t do a hard sell,” Glanzer said.