Condense and Compress: Our Custom Binary File Format

By Arseny Kapoulkine - May 23, 2013

Think about the performance improvements and rendering features we’ve brought to ROBLOX in the last year. Among them are featherweight parts, fast clusters, efficient collision detection and dynamic lighting. These improvements have crushed the limits – on part count, physics simulation and aesthetic flexibility – builders once encountered and opened doors to a world of possibilities. They’ve also exposed new limits as builders have pushed the boundaries further than ever. In this article, we’ll explain how we’ve achieved an approximately 100x reduction in the file size of ROBLOX places and a 5-10x reduction in load/save time.

Physics Performance Demo: Domino Stress Test

By Kevin He - March 20, 2013

As you may recall, we recently published an in-depth article about how we’ve sped up ROBLOX’s physics by 2-4x as a result of modeling collisions using impulses rather than springs. The “impulse solver,” together with three recent bug fixes, has drastically improved the performance and realism of one of our favorite physics-engine stress tests: Ultimate Dominoes! by armitroner. In this test, a single force cascades through thousands of standing parts, causing them to topple in quick succession.

Automated Web Testing: Where Quality and Efficiency Meet

By Andrew Haak - February 27, 2013

In this article, web engineers Antoni Choudhuri and Brandon Chothia discuss ROBLOX’s commitment to quality via automated web testing, and what the future holds for our testing infrastructure.

ROBLOX is a growing company – just look at our Jobs page to see the variety of positions we’re looking to fill – and our expansion is enabling us to develop and release features faster than ever before. While we’re producing a greater quantity of features, we’re just as importantly placing a greater emphasis on the quality of everything we do. One of the ways that has manifested itself is the expansion and improvement of our testing infrastructure for Roblox.com.

Impulse Solver Gives ROBLOX’s Physics a Serious Speed Boost

By Kevin He - February 23, 2013

In late 2012, a significant fraction of ROBLOX developers worked together to make games run on performance-constrained hardware (iPad, iPhone and iPod touch, to be exact). The team set off on an exhaustive hunt for inefficient processes within the ROBLOX source code, then found ways to optimize the problem areas that had substantial performance payoffs. This allowed us to bring the full in-game multiplayer ROBLOX experience to mobile devices in December, but we did have to make a concession: there would not be a destructible environment in ROBLOX Battle. The physics simulation was too resource intensive.

Soon, that’s going to change, as Kevin He has altered the way ROBLOX handles collisions – one of the major components of our distributed physics engine. Better yet, you’re about to see a 2-4x increase in physics performance across all games and hardware.

Dynamic Lighting and Shadows: The Voxel Solution

By Arseny Kapoulkine - February 7, 2013

Graphics gurus Simon Kozlov and Arseny Kapoulkine have been hard at work prototyping a ROBLOX lighting system that uses voxels to create dynamic shadows and lights that can be placed anywhere.

A constant challenge for us is improving the ROBLOX world while keeping it scalable–as much as we want ROBLOX to look and feel like a triple-A video game, we have to make sure a wide range of hardware can handle it. With that in mind, we’ve created a lighting and shadows prototype that not only drastically changes the look of our game, but can also run on a range of different machines. In order to create this new look, we’re developing a dynamic light and shadow engine where most of the heavy lifting is done on the CPU (instead of the graphics card) and we’re leveraging a voxel-based data structure to do it.

Fast Parts: Rendering Moving Parts 4-5x Faster in ROBLOX

By Arseny Kapoulkine - January 18, 2013

With our recent release of featherweight parts we drastically lightened the load, so to speak, of objects in the ROBLOX graphics pipeline. In an effort to continue down this path, we’re developing a system that can switch between featherweight and non-featherweight parts on the fly, in real time. We like to keep things simple around here, so we’ve elected to call them fast parts.

Why would you want to be able to switch? What are the benefits? What type of hardware will be able to handle these new parts? These and many other questions will be answered in this article. Let’s brush over the basics first.