Today we’re making our way to the Interloper in this week’s developer update!
One of the locations in the solar system that has changed the most since the alpha is the Interloper, which is an icy blue comet in a stretched ellipsoid orbit around the sun. Because of it’s unusual orbit, it oscillates between the dark outer reaches of the solar system and making a close pass by the surface of the sun, creating a variety in how the player can interact with the low gravity of the Interloper.
The icy skate park, the Interloper.
The surface of the interloper is a mix of snow, rock, and ice that creates a slippery surface that the player can jetpack around like skating on a frozen lake. Be careful - due to the low gravity it’s easy to send yourself flying off of the surface and into the void of space! Making this experience smooth required many iterations of the terrain geometry to ensure that the player is always able to see over the curve of the planet so that they can adjust their path as they skate across the surface.
On the art side, the Interloper is made almost entirely from unique geometry, due to the specific nature of the greybox. The Interloper uses techniques similar to what we’ve detailed about how we made Ember Twin and Dark Bramble, as well as many hand-sculpted terrain pieces that were necessary for the ice skating elements.
The ice at the tail of the Interloper.
One of the key visual elements of the Interloper is its translucent ice, which we achieved using a shader that we use across the game for a variety of unique surfaces: a custom bidirectional reflectance distribution function (BRDF) shader. Simply put, a BRDF is a bit of math used in computer graphics to describe the way that light interacts with a surface.
The BRDF Texture Look Up for our comet ice material. The horizontal axis represents the viewing angle of the camera to the surface, while the vertical axis represents the angle of the light to the surface.
For common material and surface types, like wood or metal, the BRDF is fairly well defined and optimized by pre-existing Unity shaders. Our custom BRDF shader allows us to create more unusual materials by deriving the surface properties from a 2D texture. While it’s not an intuitive process (and not physically accurate to real-world lighting models), it gives our artists complete control over lighting on certain materials to give the impression of more complex lighting models, such as in the case of translucent ice.
A shot of our ice material in-game. We have a lot of fun using the Little Scout’s lantern to test different lighting setups on our art assets from different angles.
We wanted to give you all a heads up that Outer Wilds will be at PAX West! More details in the coming months:
PAX West is August 31st through till September 3rd 2018 in Seattle, WA.
Updates on our games, our process, and the joys of being Mobius Digital.