The contact recycle distance, in meters. Setting this to zero disables contact point recycling. Contact recycling reuses contact points across simulation time-steps when the relative movement is small. This feature improves stability and performance by around 25% (approximately). Contact points are not recalculated until shapes move more than 5cm (default) relative to each other. Contact recycling skips some updates such as friction, pre-solve (etc) until the contacts are no longer recycled.