When "Evidence," Chinese artist Ai Weiwei's biggest exhibition to date opened in Berlin last week, one person was notably missing from the guest list: the artist himself.

Barred from traveling abroad since his release from detention in 2011, Mr. Ai couldn't be in Germany—or in New York. There, his first museum show in the city opens at the Brooklyn Museum April 18 and runs through Aug. 10.

But Mr. Ai says that in some ways Germany in particular surrounds his home in Beijing every day. "When you walk in Beijing now you almost think you're in a German industrial city, because you see all these Mercedes-Benzes and BMWs everywhere," Mr. Ai, who owns a Volkswagen VOW3.XE +1.08% Volkswagen AG Non-Vtg Pfd. Germany: Xetra ^€195.75 +2.10 +1.08% April 17, 2014 5:35 pm Volume : 1.00M P/E Ratio 10.48 Market Cap€89.74 Billion Dividend Yield 2.07% Rev. per Employee €343,937 19819619419210a11a12p1p2p3p4p5p 04/21/14 UAW Withdraws Objections on Vo... 04/20/14 Toyota Revs Up Ambitious Plans... 04/19/14 Volkswagen Seeks to Boost Vehi... More quote details and news » VOW3.XE in Your Value Your Change Short position and frequents a bar popular with German engineers, said in a Skype interview from Beijing last week.

Chinese hunger for German products triggered one piece in Berlin: eight vases from the Han Dynasty (202 B.C.—220 A.D.) dipped into the most popular Mercedes-Benz and BMW car paints in China. The altered antiques speak of consumerism, but also of the economic freedoms Chinese citizens enjoy today, Mr. Ai said.

The artist and his studio designed the new exhibitions, and a May show with art for sale at London's Lisson Gallery, to raise Mr. Ai's profile even higher than it is—while China still refuses to issue him a passport. It's a clear push for large exposure, simultaneously in three cities on two continents, at a prime season for art sales and tourism.

Mr. Ai says he is addressing two audiences: one foreign, one domestic. The artist hopes that Chinese tourists, whose presence has sharply risen in the West, will be exposed to his art and issues. "Because my work is banned from being shown inside China, the only way they can become aware of it is from the outside," he said.

The Brooklyn show "According to What?" originated in 2009 at Tokyo's Mori Art Museum, with later stops in Washington, Toronto and Miami, but Brooklyn's version includes several major new pieces. Social injustice and sexual discrimination are key themes in the artworks. Among five videos screening in Mandarin with subtitles, the new "Stay Home" documents the anguish of a woman who contracted HIV from a blood transfusion. Many Chinese still think of those with HIV/AIDS as promiscuous pariahs, to which Mr. Ai is trying to draw attention, says Sharon Matt Atkins, curator of the Brooklyn show.

Another added artwork in the roughly 13,000-square-foot Brooklyn show involves sex worker-activist Ye Haiyan, a close friend of Mr. Ai's. Ms. Ye has for seven years pushed to widen health-care access for Chinese prostitutes and petition the government to legalize prostitution and destigmatize rape and AIDS. Ms. Atkins said that last summer Ms. Ye fled to a hotel after being kicked out of her apartment in the wake of the publicity over her sex activism.

At the Brooklyn show, Mr. Ai created wallpaper that covers a room and portrays Ms. Ye's belongings including a phone, a teapot and a Guy Fawkes mask. Jumbled in front of the wallpaper are many of Ms. Ye's actual possessions—including her fridge, rolling suitcases and her Tiffany-blue moped.

Several subjects show up both in Brooklyn and the much larger German show, at the Martin-Gropius-Bau exhibition hall. In a debut, Berlin features a replica of the detention room where Chinese authorities held Mr. Ai in 2011 for 81 days. Visitors can sit on his bed, at the desk or touch the toilet. "I was in jail, I was beaten, I was forbidden to go on the Internet—all because of thoughts that were inside my mind," said Mr. Ai in the video interview.

In the same vein, Brooklyn is showing "S.A.C.R.E.D.," a sextet of less-than-life-size dioramas featuring scenes from Mr. Ai's life in detention. "S.A.C.R.E.D." has only been seen during last year's Venice Biennale.

The artist added that he has consistently received "strong support" from Germany. Chancellor Angela Merkel lobbied for his release from detention and he keeps a life-size cardboard cutout of her in his studio. Though some Americans have openly supported him, he says he still believes, as he stated in 2009, that America's approach to human rights abroad is becoming insular: "If it is not necessary, most people don't try to share the pain and struggle of others. That is just how society is."

Politics doesn't occupy all the space at the new shows. The artist's love of Marcel Duchamp, the father of conceptual art whose work Mr. Ai discovered while living in Brooklyn in the 1980s, is present in the New York exhibition through a wire bent in the shape of Duchamp's face.

The artist's work often revolves around Mandarin puns that can get lost on Westerners. One such work displayed in both shows (and part of the U.S. tour from the start) is "He Xie," a pile of 3,200 hand-painted porcelain crabs. The Mandarin word means both "river crabs" and "harmonious society," but also designates the "Gang of Four," disgraced leaders who were tried in 1981 for treason.

In 2011, authorities bulldozed a studio that they had invited him to build in Shanghai in 2008. Mr. Ai first tried protesting. When that failed, he planned a feast of river crabs at the site and went on to create the porcelain crustaceans.