Evan Parker

Bringing Google earth to virtual reality

Since its inception, Google Earth has been brought to a variety of platforms: from desktop to mobile devices, from native to web. This talk discusses bringing Google Earth to virtual reality, a platform that poses unique challenges in user interaction and rendering. We present solutions to help users navigate planet-sized worlds in VR without losing context or becoming nauseous, and talk about techniques used to render such large worlds at the steady high frame rates that are required for VR.

Earth in Google maps: rendering trillions of triangles in JavaScript

JavaScript is not typically associated with high performance rendering. This talk covers techniques that were used to bring the massive data set of Google Earth into a web browser using standard JavaScript and WebGL. The client has access to a 3d model of the entire world, an ever-growing data set stored in servers, and the client needs to fetch and display any views (see Figures 1 and 2) of it very quickly with a limited memory budget of few tens of megabytes. The total data set, on the other hand is measured in trillions of triangles and their associated textures. The talk describes the hierarchical subdivision and the data layout used to manage this complexity. Level-of-detail mechanisms are used to render objects at different scales and to provide a quick preview when high resolution data is still loading. The unpredictable network bandwidth and latency pose additional challenges. The talk describes the algorithm used to decide which data should be 1) requested, 2) evicted, 3) kept in memory, or 4) rendered. Rendering of map elements such as roads and labels is more challenging in 3d than on a 2d map. The talk describes techniques that were used to render vectors and labels quickly at right location on the surface of the 3d terrain. JavaScript was not originally designed for high performance realtime use. For instance, the garbage collector may kick in at any point pausing the execution for tens of milliseconds. The talk describes the memory management techniques used to avoid this. To optimize for stable frame-rate and quick load time, tasks have to be carefully scheduled such that data processing and rendering can happen seemingly at the same time. The talk describes how the work was scheduled in the main execution thread and in Web Workers. To make the Earth appear realistic, atmospheric attenuation needs to be modeled accurately. The talk describes how the atmosphere and the real-time clouds are rendered.

The making of Google earth VR

One of the great promises of virtual reality is that it can allow people to visit places in the world that they might otherwise be unable to. Since the recent renaissance of virtual reality, content creators have exercised various techniques such as 360-degree cameras and photogrammetry to make this promise come true. At Google, we spent more than 10 years capturing every part of the world as part of the Google Earth project. The result is a rich 3D mesh that contains trillions of triangles [Kontkanen and Parker 2014] and as such is predestined to be a good data source for VR content. In [Kaeser and Buehlmann 2016] we discussed some of our early experiments with bringing Google Earth to virtual reality, but without a focus on developing a product. Following these experiments, we worked extensively to create a well-rounded product, Google Earth VR, which we eventually launched to the world in November 2016. Google Earth VR quickly became one of the most actively used VR applications in the market and has won several awards since. This talk discusses the journey of the Google Earth VR project from its early prototypes to its final launched stage.