Erin Catto

About:

Erin Catto works in the video game industry and created Box2D, a 2D physics engine, sharing updates on game physics and programming.

Website:

box2d.org

Specializations:

Video Game Industry Professional Creator of Box2D Game Developer

Interests:

Game physics Programming

Incoming Links:

Boris Chema Guerra Erik McClure Tony Wang

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2025-04-19 • software development physics 2d graphics

Box2D version 3.1 is a significant update that addresses bugs and build problems, introduces new features and refinements, including experimental character mover support, a new sensor system, rolling resistance and tangent speed a...

2024-08-27 •

The text discusses determinism in game development and physics engines, focusing on algorithmic, multithreaded, and cross-platform determinism. It also touches on roll-back determinism and the challenges it presents in multiplayer...

2024-08-19 •

The text discusses the use of SIMD in game development, particularly in the context of Box2D. It explains the challenges of using SIMD in game development and how the author implemented graph coloring to enable SIMD processing. Th...

2024-08-09 •

The author announces the release of Box2D version 3.0 after 18 months of work. The new version includes speculative collision, API changes, moving to C from C++, performance improvements, addition of capsules, soft step solver, im...

2024-02-05 •

The text discusses the author's experience with testing Box2D version 3.0 alpha and the stability problem encountered. This led to the creation of Solver2D, a simplified engine designed for testing multiple different solvers. The ...

2023-10-08 •

The text discusses the fundamental low level feature of physics engines, island management, and its impact on solver design and performance. It compares three approaches for island management: Depth-first search (DFS), Parallel un...

2023-01-15 •

The author started working on version 3.0 of Box2D over the holidays. They made good progress in their research and realized that this would be a major update to Box2D. They explained their goals for version 3.0, including specula...

2020-06-21 •

The text discusses the problem of ghost collisions in game physics, particularly in Box2D. It explains how chain shapes are used to eliminate ghost collisions and support smooth collision. The text also delves into the use of Voro...

2020-04-12 •

The text discusses computational geometry algorithms relevant for preparing collision data, such as convex hull, mesh simplification, and convex decomposition. It explains the importance of convexity for dynamic objects and the ch...

2020-04-03 •

Box2D has support for continuous collision. The Box2D continuous collision algorithm uses a time of impact (TOI) collision algorithm along with time sub-stepping for the response. Joint limits can also suffer from fast movement. A...

2020-01-01 •

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2018-09-05 •

The text explains how to transform a plane equation in local space into world space using a transform. It provides the equations and steps to find the plane offset in world space.

2018-07-07 •

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2018-06-24 •

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2014-08-07 •

The text discusses the concept of dynamic trees and the importance of keeping them balanced to avoid degeneration into a linked list. It compares the balanced tree using a surface area heuristic in Box2D with the unbalanced tree u...

2014-02-03 •

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2014-01-31 •

The author encountered a problem computing a polygon normal using Newell’s method for a triangle close to the origin. The triangle has edge lengths of around 0.6320, 0.6321, and 1e-4, making it a sliver and numerically challenging...

2012-08-31 •

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2012-03-25 •

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2011-12-17 •

The text explains how to deal with the difference between meters and pixels when working with Box2D. It suggests converting length units from pixels to meters when passing values from Box2D and vice versa to improve the stability ...

0001-01-01 •

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