SAO PAULO.- Just inside the door to the studio of Brazilian artists Osgemeos is a self-portrait.

Spray-painted on the concrete wall of the old metal workshop’s entryway, the image shows identical twins Otávio and Gustavo Pandolfo, 50, standing next to each other, hands at their sides and looking forward. They’re wearing colorful printed clothing, bags slung over their shoulders and baseball caps propped on their heads.

Their skin is the same shade of yellow as the other characters they’re known for throughout their art, a nod to the fact that they, too, might be from Tritrez, the fantastical world they explore in their graffiti-style murals, monumental sculptures, intricate drawings and vivid paintings that have, for more than three decades, rocked their native Brazil.

The self-portrait is just a snippet of what’s to come after passing through a small doorway at the back of the room that leads to a workspace that allows the twins to create on an enormous scale. Here, preparations are underway for “Endless Story,” their first museum survey of work in the United States. The full-floor presentation will run at the Smithsonian’s Hirshhorn Museum, in Washington, D.C., from Sept. 29 to Aug. 3, using the circular museum and its outside gardens to showcase about 1,000 artworks, photographs and archival materials.

One of the brothers’ imposing sculptures, wrapped in black plastic so that it can be shipped for the exhibition, hangs from chains on the sweeping ceiling and another is tucked away in a corner, a smidgen of what looks like a subway car visible.

Under the studio’s mezzanine sits a model of the Hirshhorn, miniature versions of paintings and a photo of the pair as teenage B-boys placed on tiny gallery walls as the brothers decide where they should go. Working with curator Marina Isgro has been a massive undertaking — not only do the artists have to select pieces they’ve done since art became their profession, but they also have to comb through the thousands of drawings their mother saved that they did as boys. Some depict sketches of cars and fire trucks, while others are an attempt to explain to their parents the importance of Tritrez to their journey.

That magical world is also the focus of a solo exhibition at Lehmann Maupin gallery in New York. “Cultivating Dreams,” their sixth solo show with the gallery, runs through Aug. 16 and features 13 new paintings and an immersive installation, taking visitors through Tritrez, a dreamworld they first started drawing when they were just 5 years old.

Coming out of the world of graffiti and street art, Osgemeos “have made the art world look at them in more of a formal way, as sculptors and painters and storytellers,” said David Maupin, co-founder of Lehmann Maupin. “They have that ability to do both: from outdoor murals to indoor paintings. I can’t think of many artists who have been able to occupy both of those spaces, both of those worlds.”

That didn’t happen by chance. Although their foray into art began as a way to share the spiritual world of Tritrez, they don’t hide the fact that part of what drives them is their ambition.

“For people like us, who didn’t go to art school, who are self-taught, it’s a difficult space to penetrate,” Gustavo said of the formal art world. “To be able to get this kind of recognition, to be able to live from your work as an artist is really gratifying. Every artist should be valued and recognized. We’ve always believed that the recognition of one artist is an open door for other artists.”

American artist Barry McGee was that door-opener for Osgemeos.

It was 1993, and the twins were 19 years old when he first phoned their house. McGee, who got his start as a graffiti artist in 1980s San Francisco, was in their hometown, Sao Paulo, thanks to a grant from the Lila Wallace-Reader’s Digest Fund.

McGee was introduced to well-known contemporary Brazilian artists, but he still felt like he was missing out on what was happening in the streets. Until one day, while riding his bike around the Vila Mariana neighborhood where he was staying, he saw a massive mural of B-boys break dancing painted by Osgemeos.

“I hadn’t seen any work in my life that looked like theirs,” he said. “It was very elaborate and it was already distinctive at that point.”

Brazil is known for a type of graffiti called pixacao, a cryptic lettering style rooted in protest against corruption and inequality. The streets of Sao Paulo were covered in it then, so Gustavo and Otávio’s detailed and colorful character work stood out next to the stark letters and symbols.

It was tagged as “GEMEOS,” and there was a phone number sprayed in the corner. McGee wanted to know who the artists were, so he called them. The twins’ mother, Margarida Leda Kanciukaitis Pandolfo, answered the phone. She invited him to the family’s home to meet her sons and sit down for a traditional Brazilian meal of feijoada, a stew made of black beans, beef and pork.

It wasn’t until they started to talk at the dinner table that the brothers realized who McGee was.

“We were like, ‘Oh, my God, this is Twist,’” Gustavo said, referring to one of McGee’s most well-known monikers. The twins had been admiring his graffiti in skateboarding magazines for years and were floored that the artist wanted to get to know them.

From there, the trio, who are still friends today — and are currently sharing exhibition space at Lehmann Maupin — became inseparable. They spent hours together holed up in the twins’ room drawing on old magazines or wandering Cambuci, the Sao Paulo neighborhood where the brothers lived.

Masters at “getting invisible,” as graffiti artists say, they swiftly did what they had to do and got out without being noticed. One twin would do lettering while the other worked on outlines, each taking turns spraying while the other watched his back.

“They’re like that in everything they do,” McGee said of the seamless and silent way the twins work together. “They’re like that out in the street and in the gallery.”

As teenagers, their work was heavily based on hip-hop culture, which they immersed themselves in after seeing older boys break dancing in front of their parents’ house.

“We didn’t even really know what that was yet,” Gustavo said. “But what was interesting to us was that they were spray-painting the walls. Right away, we associated that with our drawings. If they can spray-paint buildings, then we can spray our drawings on them too.”

Three or four years before meeting McGee, Otávio and Gustavo got to know Speto, a pioneer of graffiti in Brazil. Then, their art featured innumerous images of B-boys and DJs, sprayed with cans of automotive paint. They were difficult to manipulate, but the only kind available in Brazil, which was coming out of a 21-year military dictatorship that left the country scarce on resources.

Through Speto, who also worked in animation, the twins learned how to better create characters. Their journey would take them through some 32 styles, eventually landing them at the whimsical cast of yellow-skinned, bigheaded characters they create today. Surreal pieces that show everything from faces swinging open on hinges, to body parts disappearing into or climbing out of the walls they’re painted on, their work still has elements of hip-hop — characters often carry boomboxes or turntables and some have cans of spray paint in hand.

“Their vocabulary has not changed, but evolved,” Maupin said. “Their sense of color and experimentation has evolved.” He added: “The backgrounds have become much more complex. They’ve become much more baroque.”

The many styles they’ve been through — from geometric to free-flowing stream-of-consciousness — will be given their own space at the Hirshhorn. “We like to aggregate the things we’ve done over the years into the work we do now,” Gustavo said, sitting in the office of their studio in Cambuci, just a handful of houses from their childhood home.

As he speaks, he sketches with a black marker on loose-leaf paper, his brother sitting across from him doing the same. The office is small and brimming with hidden pieces of history. Piles of papers scribbled on with the same markers spill onto the desk where they put down their ideas. Molds of some of their nameless characters are strewed about, and just outside the door hang pieces by McGee.

An old class photo hangs nearby, the brothers and the other 28 students all dressed in their blue-and-white school uniforms.

In it, they look to be about 5 years old, the same age they were when they started telling their parents about Tritrez, a place they describe in a similar way to heaven: they feel they lived there before they were born and say they will return to it one day when they die. “We’ve always had this strong spiritual connection with Tritrez and with each other,” Otávio said. It is, in a sense, their origin story — it explains where they came from, making a tumultuous entrance as premature babies — a magical world they wanted to replicate and share with others.

“It’s not a religion, but it’s something that has this strong link to our beginning as well as to our destiny,” Gustavo said. “It’s one life divided between two people.”

At the Hirshhorn, the pair are creating a gallery dedicated solely to Tritrez. In it will be everything from their first childhood iterations of the dreamlike world, to “The Tritrez Altar,” a rainbow-colored structure housing sculptures of their trademark characters that will be shown outside Brazil for the first time.

“The more you see of their work, the more you realize they are actually translating their inner world to the outer world,” said museum director Melissa Chiu. “It’s this impulse that they have to share. I think that’s what really makes them, in some ways, that rare kind of artist for whom categories are irrelevant.”

Their murals can be found in Lisbon, Portugal; Berlin; Mumbai, India; and New York. And major public commissions include murals for the 2004 Olympics in Athens, Greece, as well as covering the facade of London’s Tate Modern in 2008. Their pieces, which regularly sell for six figures, can be found in numerous international collections, including the Museum of Modern Art in Sao Paulo.

Success is something that they have strived for since they first started putting their whimsical world on walls around Sao Paulo. Their unlikely occupation of space in the traditional art world has now opened doors for others too.

“In Brazil, Osgemeos have given graffiti much more visibility and reach,” said Berna Reale, a Brazilian contemporary artist who, like Osgemeos, has taken her street performances into museums.

The twins welcome the change in the way people look at hip-hop culture — “it’s saved so many lives,” Gustavo said — and hope it continues to be an outlet for kids like them. Their own point-of-view is ever-changing, too, especially when it comes to the work they produce.

“We’ve never repeated a drawing,” Otávio said. “Each one is its own.”

Gustavo nodded: “There are so many ideas to put down on paper.”

They keep drawing as they talk, spinning their papers so they can get the lines just right. They’re working separately, but they move like one. It’s as if they’re there, looking at Tritrez together one more time so they can share a few more details of the magic with the rest of us.

This article originally appeared in The New York Times.