He was still looking when he met Regina Dugan, then the leader of Google’s secretive Advanced Technology and Products group, which was experimenting with virtual reality. First he partnered with the group to make a hand-drawn virtual reality short called “Duet,” a charming piece released in 2014 about two babies growing up that was shortlisted for an Academy Award. “Duet” broke new ground, since animation in virtual reality had almost exclusively been computer-generated. But though he’d spent a lifetime drawing on paper, Mr. Keane had always dreamed of being able to make the paper disappear. “The goal would be to animate not on paper but in space,” he said.

Enter Tilt Brush, which Mr. Keane encountered when Mr. Skillman introduced himself at a visual effects conference in San Francisco. Though still in a primitive state, it was maturing rapidly, and Mr. Keane soon became a convert. In September 2015, seven months before its release, he previewed its capabilities with “Step Into the Page,” a five-minute video. “The edges of the paper are no longer there,” he exclaimed in a voice-over as he did a loose, freehand sketch of Ariel in virtual space. “This is not a flat drawing. This is sculptural drawing.”

Scott McCloud, the graphic artist whose book “Understanding Comics” is considered the ultimate guide to the art form, got to play with Tilt Brush when Google invited him to its Silicon Valley headquarters in August. “I don’t mind saying, I’m a little bit obsessed with this program,” he said as we sat in his small, book-crammed office in a mall in the Los Angeles exurb of Thousand Oaks. “One thing that appeals to me the most is, it’s still very early. Everyone is asking fundamental questions. We’re still trying to figure out what people are going to use it for. I love it when technology is in that stage.”