After last week’s standout overseas start, 20th Century Fox looks to Stateside auds this weekend to keep the party going with 3D animated pic “Rio,” which as of Tuesday has cumed $64.4 million in total international grosses.

“Rio” launches today at 3,826 U.S. playdates, including 2,591 3D runs, and will expand to 19 additional overseas territories, bringing the film’s total offshore market count to 64.

While the toon is expected to easily top the weekend’s domestic box office, with a launch projected at north of $30 million, the Weinstein Co. hopes attract an older crowd for R-rated “Scream 4” with moviegoers 17-25 and older. “Scream 4,” which B.O. observers predict to bow at $24 million-$27 million, goes out today at 3,305 locations and in key overseas markets like Brazil, France and the U.K.

Both wide entries will give the U.S. market a much-needed lift as 2011 year-to-date box office totals are running 20% behind last year. Pundits expect this weekend’s new titles to jumpstart B.O. momentum going into the summer.

The expected $30 million-40 million “Rio” bow would put the toon in similar territory with last year’s breakout 3D animated film, “How to Train Your Dragon,” which opened to $43.7 million on March 26. “Rio” would also become this year’s best-yet domestic opener and see the biggest worldwide weekend take.

The weekend’s wide duo are unlikely to dip into each other’s target demos too much, though “Rio” could broaden beyond families.

According to online ticketing service Fandango, “Scream 4” is scaring up 24% of ticket sales as of Thursday afternoon, with “Rio” only a shade behind at 23%. The indie adaptation of classic Ayn Rand tome “Atlas Shrugged,” from Rocky Mountain Pictures, bowing at 299 locations, surprisingly ranks third with 15% of the site’s advance ticket sales.

Roadside Attractions looks to cater primarily to moviegoers over 30 with Robert Redford’s “The Conspirator,” debuting the film at an aggressive 707 engagements.

That demo has been served nicely by recent specialty players “Jane Eyre” and “Win Win.” The former, from Focus Features, has cumed $5.5 million domestically; Stateside totals for Fox Searchlight’s “Win Win” reached $3.7 million Wednesday.

Family auds have propped up the domestic B.O. lately — good news for “Rio” as it makes its Stateside debut. Fox originally had skedded the toon to launch day and date globally last weekend but pushed back the domestic bow closer to Easter on April 24, positioning “Rio” more directly with spring break. Pre-weekend tracking suggests the film has strong definite interest among most auds, and higher 3D ticket prices will also contribute.

However, 3D shares have been declining for family films. Paramount’s 2D “Rango” stands as the year’s highest-grossing film so far at $117.9 million domestically, without 3D shoring up grosses.

With “Scream 4,” Weinstein, via its Dimension label, hopes an avid fanboy following — and a healthy number of femme horror fans — will drive weekend ticket sales. “Our hope obviously is to bring this to a whole new generation of fans,” said Weinstein prexy of theatrical distribution Erik Lomis.

The third “Scream” installment opened to $34.7 million in 2000 — the franchise’s best opening to date — though it was the inaugural outing that became a box office phenomenon in 1996, cuming ($103 million) more than 16 times its opening at $6.4 million.

Series’ newest offering likely won’t catch fire the way the original did, but nostalgia for the first three films, added to a decade-long gap between “Scream 3” and “Scream 4,” could fuel a better-than-expected opening weekend take.

Universal’s holdover “Hop” has performed better than industry expectations with a cume of $70.6 million domestically, though the Easter bunnies will have to fend off their feathered “Rio” friends for attention from family auds in its third sesh.

And among the frame’s quartet of soph sesh players, Focus Features’ “Hanna” and Sony’s “Soul Surfer” may stand the best shot at maintaining speed after last weekend’s solid debuts. “Soul Surfer,” with totals to date at $12 million, received the best exit poll ratings of its fellow openings, while “Hanna,” with $15.2 million, has been posting solid mid-week figures, second only to “Hop.”