“Tilt Brush is designed for creators — whether you’re a casual doodler or a professional artist,” says Google Product Manager Elisabeth Morant. “Over time, we’ve seen the product used in ways we never would have imagined — from bringing our favorite Disney characters to life, to prototyping what became a Time Magazine’s best of 2018 invention, to 3D printing and casting a Tilt Brush self portrait as a bronze statue. The possibilities are endless, and we’ve only just scratched the surface.”

We sat down with Morant to learn more about Tilt Brush and the work it took to bring this impressive creative tool to an all-in-one VR system.

What was the initial inspiration behind Tilt Brush? How has it changed over the course of development?

Elisabeth Morant: From the very beginning, we found that Tilt Brush resonated with two core audiences. On the one hand, we had our creators, who were excited by the possibilities of creating art never before possible with this unique new medium. And on the other hand, we found over and over people (consumers and developers alike) told us that Tilt Brush was their very first introduction to VR — or at least, room-scale VR. It’s been important to us for the lifetime of development that we continue to build features that raise the skill ceiling of what’s possible for creators, while also making sure the product is easy to pick up and use for first timers.

Why did you decide to bring Tilt Brush to Quest?

EM: When we learned that Oculus was building a cord-free standalone headset, we knew we had to bring Tilt Brush to Quest. This new form factor will unlock completely new opportunities for our artists to create. We’ve already seen dancers adopt Tilt Brush to visualize their movements in VR, but the opportunity for fully free movement and creation will lead to art that we never could have dreamed up before.

How did you go about bringing Tilt Brush over from PC VR to a mobile chipset?

EM: Most of our work porting Tilt Brush to Quest focused on performance improvements. Luckily, some decisions we made early on set us up for early performance wins. For example, instead of recreating stroke meshes on the GPU for every frame, Tilt Brush strokes are converted from their internal control point representation into geometry only once: either when the user first creates the stroke, or when the sketch is loaded from disk. The GPU then just has to render a list of pre-generated triangles. Another early easy win for us was to switch over our stroke rendering from double-sided to single-sided, using the shader to draw the reverse side of the stroke, and instantly halving our triangle count.

We also had to make a few visual changes as well. For example, the PC version of Tilt Brush uses a full-screen pass to render selected objects, perform a blur on them followed by a threshold to create an outline effect. Doing a full-screen effect that would involve a read-back was not feasible on mobile. We tried various options to do outlining on strokes, and in the end we chose to go for a solution that looked completely different: