“We’re making pretty good progress on making it so that it has mobility that is sort of within shooting range of yours,” Dr. Raibert said, referencing the video at a recent conference. The video of Atlas moving through the woods was made last year with the 2013 version of the machine, a representative, Maria Silvaggi, said in an email on Tuesday.

Atlas, first publicly unveiled in 2013, received funding from the Pentagon’s Defense Advanced Research Projects Agency, but that relationship has ended, a representative said Tuesday. Scientists believe that the robot could eventually assist humans after disasters, like earthquakes and fires, going where rescuer workers cannot. But for the scientists, development can be maddeningly slow.

For Atlas, an aluminum machine weighing over 300 pounds, the training process looks grueling: Researchers kick the robot, throw weights at it or make it walk over rock beds to observe how well it adapts to challenges. On the rock bed, Atlas can be seen tottering but rushing to complete the course, a move, Dr. Raibert said, that mimics the behavior of people and animals — when we’re on unsure footing, our instinct is to keep moving forward, and fast.

Leaving the controlled setting of a lab presents its own hurdles.

“Out in the world is just a totally different challenge than in the lab,” Dr. Raibert said. “You can’t predict what it’s going to be like.”