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 Dead Reckoning
 Using Cubic Splines

 Printable version


A common problem when writing networked virtual environments is overcoming the lag inherent to the Internet; players seem to jerk about the field of play as new data packets are incorporated. Common solutions include increasing the frequency of packets sent, reducing packet size through compression, and most importantly, dead reckoning. This article will attempt to explain a technique for eliminating the "jerk" of lag by employing the power of cubic splines in a dead-reckoning algorithm.

What is Dead Reckoning?

Before jumping straight into cubic splines, a brief description of dead reckoning is required. Programmers use this technique to reduce the effects of lag in a game by trying to guess that an object takes. Dead reckoning makes its guess based on the object's characteristics. For example, if an object has a known starting position and velocity then its path can be created using simple physics. The paths created can be applied to the object, creating the illusion of smooth motion. Cubic splines are a kind of dead reckoning that creates a smooth transition between two data points.

Next : Possible Forms of Dead Reckoning

This article may not be reprinted commercially without the express permission of the author.
Copyright © 2000 Nicholas Van Caldwell