An architect by training, Mr. Ubelmann, 36, had worked in Syria before the country was engulfed by war. But now there was special urgency for the kind of work his youthful team of architects, mathematicians and designers did from their cramped offices in Paris: producing digital copies of threatened historical sites.

Palmyra, parts of it already destroyed by the Islamists who deemed these monuments idolatrous, was still rigged with explosives. So he and Houmam Saad, his Syrian colleague, spent four days flying a drone with a robot camera over the crumbled arches and temples.

“Drones with four or six rotors can hover really close and register structural details, every crack and hole, and we can take very precise measurements,” said Mr. Ubelmann, who founded the company Iconem. “This is the stuff architects and archaeologists need.”

They need it in a new push for virtual preservation that scientists, archaeologists and others, like Mr. Ubelmann, are compiling on a large scale. The records could be used to create computer models that would show how monuments and endangered historical sites might one day be restored, repaired or reconstructed.

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Many of the 40,000 images he and his team took at Palmyra have become the basis for displays. Called “Eternal Sites: From Bamiyan to Palmyra,” the show aims to draw attention to the rising threats to global heritage.

To underscore the exhibition’s political importance, it was opened several weeks ago by President François Hollande of France, who described it as “an act of resistance” against terror and intolerance. Showing the beauty of the Middle Eastern heritage, he said, “is the best answer to the Islamist propaganda of hate, destruction and death.”

Jean-Luc Martinez, the director of the Louvre and the lead curator of the show, said the sites had been chosen because “all are under threat from pillaging, neglect or destruction and are not accessible to the public.” He said it aimed to mobilize public opinion “in the face of the devastation of unique heritage.”

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The exhibition in Paris, which is drawing large crowds, coincides with “History Begins in Mesopotamia,” a show at the Louvre’s regional museum in Lens. Both exhibitions highlight the French government’s active concern about cultural damage in Syria, which was briefly controlled by France in the first half of the 20th century.

Mr. Hollande has taken a strong interest, condemning the deliberate destruction of patrimony by all sides as “war crimes.” This past month, France offered $30 million toward a proposed $100 million fund to protect sites as fighting abates, provide emergency storage for artifacts and eventually rehabilitate monuments.