GDC is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

View, browse, and sort the ever-growing list of sessions by topic and format.

For more information about conference topics and session formats, visit the GDC Showcase Conference page.

Replicating Chaos: Vehicle Replication in 'Watch Dogs 2'

Matt Delbosc  (Team Lead Programmer, Ubisoft Toronto)

Date: Friday, March 19

Time: 1:00 pm - 1:30 pm

Track: Programming

Format: Discussion Session

Vault Recording: TBD

This GDC 2017 talk will feature real-time interaction with the speaker through online chat messaging during its scheduled broadcast. Accurate peer-to-peer replication of game objects in a highly chaotic physical simulation is essentially an unsolvable problem. This session will explore the techniques used in 'Watch Dogs 2' to replicate vehicle trajectories, compensate for network latency, and realistically represent vehicle-versus-vehicle collisions between players. This talk will discuss several well-known techniques such as projective velocity blending, snapshot buffering, and physics simulation blending, and present practical approaches for combining them together. Results from the game will be shown, along with a discussion of unsolved problems and future research direction.


Attendees will learn about techniques that can be used to support replicated physics-based gameplay, how these techniques can be applied in practice, and the trade-offs and complexities of applying them to real situations.

Intended Audience

This is intended for most levels of network programmers, so some basic knowledge in that area is required. Beginners should benefit from learning the common techniques, and intermediate programmers should take away some lessons about solving the more complex issues with synchronizing physics collisions over the network.