The quiet Walnut Creek software house whose finite-element math holds up the world's tallest buildings.
THE MARK OF THE ENGINEERS' ENGINEER. The CSI wordmark - a logo you have never seen on a billboard, yet one whose software sits beneath skylines on six continents. Photographed as a company profile portrait, Vincent Musi style: the subject looking straight into the lens, nothing to hide.
There is a category of company that never trends, never rings the opening bell to a roar, and never leaves the industry it serves. Computers and Structures, Inc. is one of them - and almost every tall building you have ever walked past owes it a quiet debt.
Fifty years ago, a young structural engineer named Ashraf Habibullah made a bet. He wagered that engineers designing buildings and bridges would rather trust software than slide rules and hand calculations. In 1975, in Berkeley, California, he founded Computers and Structures, Inc. to make good on it. The company commercialized a line of research - the Structural Analysis Program, or SAP - that Habibullah's mentor, UC Berkeley professor Edward L. Wilson, had begun in 1969. Together they also built ETABS, a program written specifically for the peculiar problem of getting multi-story buildings to stand up.
Half a century later, CSI is headquartered a few miles east in Walnut Creek, with a second office in New York. It employs roughly 230 people. It does not, by tech-industry standards, look like a giant. And yet its software is used by structural engineers in more than 160 countries, on projects that define the world's skylines: the Burj Khalifa in Dubai, Taipei 101, One World Trade Center, the Beijing "Bird's Nest" Olympic Stadium, the Centenario Bridge in Panama. Before a single beam of the Burj Khalifa was raised, the world's tallest building existed as a mathematical model inside ETABS.
"CSI is recognized globally as the pioneering leader in software tools for structural and earthquake engineering." — Computers and Structures, Inc.
At its core, CSI sells confidence. A structural engineer feeds a design into one of its programs - the geometry of a tower, the loads it must carry, the way the ground shakes in an earthquake - and the software applies the finite-element method to predict how the real structure will behave. Will a floor slab crack? Will a bridge deck sway too far in the wind? Will a building survive a magnitude-7 quake, or fail?
These are questions where being wrong costs lives, which is precisely why CSI built a business on getting the math right - release after release, code update after code update. The company's staff includes not just programmers but licensed structural engineers, researchers and academicians, a lineage that runs straight back to the Berkeley research bench.
CSI's customers are the firms that design the built world: structural and earthquake engineering practices, bridge and infrastructure designers, contractors, government agencies and universities. When engineers argue about which structural software is best, the debate almost always starts with a CSI product - because becoming the tool your industry benchmarks against is worth more than any advertising campaign.
The problem CSI solves is deceptively simple to state and brutally hard to solve: reality is nonlinear, materials fail in complicated ways, and the ground moves. Hand calculation cannot capture a 160-story tower's response to a design earthquake. CSI's software can - and it does so within workflows engineers already know, now increasingly linked to Building Information Modeling. In 2025 the company added data exchange between Autodesk Revit and SAP2000, ETABS and SAFE, letting the analysis model and the coordination model speak to each other.
Where does CSI sit in the market? Squarely in the middle of it, as the incumbent standard. Its rivals are formidable - Bentley Systems' STAAD and RAM, Autodesk's Robot Structural Analysis, Germany's Dlubal, Trimble's Tekla Structural Designer, Nemetschek's SCIA. What sets CSI apart is neither price nor marketing noise. It is a five-decade reputation, built one validated release at a time, that its model matches the real thing. In earthquake engineering, that reputation is the product.
STRUCTURAL HEIGHT (METERS) OF ICONIC PROJECTS MODELED IN CSI SOFTWARE · SOURCE: PUBLIC PROJECT RECORDS
The heights vary; the tool underneath does not. Different countries, different architects, one common structural engine.
CSI's model is straightforward and durable: it licenses proprietary desktop software to engineering firms, agencies and universities through perpetual and subscription licenses, backed by maintenance plans, training and technical support. Revenue flows from professional seats sold across a global network of direct sales and resellers. Third-party estimates put annual revenue in the region of $25 million - modest for a company of its reach, and a reminder that influence and headcount are not the same thing.
It is a business that rewards patience. The software gets a little better every year, the installed base compounds, and the switching cost - retraining a whole engineering department - keeps customers loyal. Consistency, in this market, is a growth strategy.
The "SAP" in SAP2000 traces to Edward Wilson's 1969 Berkeley research code - not a marketing name.
The Burj Khalifa was analyzed in ETABS before construction - the tallest building, born first as math.
Habibullah co-founded Diablo Ballet in 1993 and runs an arts nonprofit for engineering students.
Software used in 160+ countries, run from a quiet office in Walnut Creek, California.