New York artist Heather Dewey-Hagborg says the project started from a desire to explore what could be discovered from an "artifact" someone has left behind.
"The idea for the project came from this fascination with a single hair," she told CNN.
"You want something that is relatively fresh. Nothing that has been stepped on or that looks like it's been sitting around for ages."
The DNA information is then extracted in the lab and then fed into a computer to generate the 3D model of a face.
Ms Dewey-Hagborg says a lot of information can be decoded in the process.
"From a cigarette butt, I can learn where someone's ancestors likely came from, their gender, eye color, hair color, complexion, freckles, their tendency to be overweight and a handful of dimensions of the face as well with a certain likelihood," she said.
She says the face model that is produced is not an exact replica of the face of the stranger who unwittingly provided their DNA.
"It's important to understand that these portraits are a general likeness. They're not exact reconstructions," she said. "They'll have things in common with the person, but they won't look exactly like the person."
