Smoothing ROBLOX Character and Vehicle Motion

By Kevin He - October 27, 2012

When you see ROBLOX characters moving in-game, their motion occasionally appears to “stutter.” The problem is magnified in certain scenarios; for example, two characters standing in close proximity on a moving conveyor will appear to stutter dramatically in each other’s camera. ROBLOX Client Physics and Networking Lead Kevin He recently dove deep into this problem, as it applies to characters and vehicles, and has some observable improvements to share.

First off, let’s take a look at some before-and-after video. In both clips, there are three players in a vehicle and the video is captured from the camera of a non-driver passenger. On the “new” side, it’s clear that much of the vehicle’s motion stuttering has been eliminated.

Enhanced Water Physics, Vehicle Seats Support Rear Propellers

By Kevin He - September 25, 2012

We’ve talked previously about our ongoing effort to build robust joints and motors, and even touched on implementing seats for boats that support rear propellers. We’re still ironing out bugs with our soon-to-be released robust joints and motors, but we decided to release our new boat seat and water propeller support first. These features function independently, letting you experiment with propellers and watercraft today. Though this blog post features some pretty complex ideas in terms of building, we are hard at work on streamlining these building methods in the future so they’re intuitive for all uses. For now, check out what we’ve got so far.

In order to understand the changes we’ve made to ROBLOX’s water physics, let’s discuss how a propeller works, particularly in water. Like tires on a car, propellers convert power into forward motion by rapidly spinning at just the right speed, velocity, and most importantly, angle. The faster they spin, the faster your water-based vehicle should propel forward.

Robust Joints and Motors: Keys to Better Vehicles in ROBLOX

By Kevin He - July 27, 2012

At ROBLOX Game Conference 2012, Kevin He dissected the steps he’s taken to refine ROBLOX’s water physics, hinges and motors so that vehicles – especially boats – perform more realistically. In this blog post, we’re recapping the key parts of the development process. You might be surprised at how much work goes into physically simulating real-world machines in a life-like fashion.

ROBLOX’s water, released in June, gives you the ability to create a boat that floats based on actual physical properties, rather than lines of Lua code. While the release of water marked a big step forward for ROBLOX, it has its limits; for example, if you want to create a propeller-powered boat, the propellers have to be on the side of the boat, as though they’re mimicking wheels on a car.

A Deep Look at ROBLOX’s Buoyancy and Water Physics

By Kevin He - April 24, 2012

Boats. Waterfalls and geysers. Swimming and diving. Flowing rivers and deep pools. With version 1.0 of ROBLOX’s buoyancy and water physics, carefully crafted and researched by our Physics Team, these things are not only possible, but also realistic. We’re featuring ROBLOX Physics Engineers Kevin He and Tyler Mullen today, as they explain the latest iteration of buoyancy (see the original here) and its implementation in ROBLOX.

Water is more than a texture in ROBLOX. It has its own unique properties and behaviors, all of which integrate into ROBLOX’s existing physics engine. Objects float on water surfaces, bob up and down with pressure changes and sink if they’re too dense. Water flows, pushing objects along its path, with user-defined directions and velocity. Players dive underwater and swim the depths or wade on the surface.