cl_smooth & cl_smoothtime

One of the biggest concerns for many cs:s players is their configuration files. These two cvars standout in particular as two of the most misunderstood as important in 'hit registration'. Lets break them down.

cl_smooth

Valve's help text states:

- Smooth view/eye origin after prediction errors.

This cvar takes 1 or 0 as it's parameters. 1 will smooth the players view after a prediction error. 0 will not smooth the players view after prediction error. Disabling this renders cl_smoothtime useless.


cl_smoothtime

Valve help text states:

- Smooth client's view after prediction error over this many seconds

If cl_smooth is 1 (enabled) AND a prediction error occurred the game will smooth the players view to the correct position over the parameter of this cvar in seconds.


By now it should be very clear that these cvars are useful only in the case of a prediction error as they function to smooth the players perspective if one occurred .
So what is a prediction error? I go over prediction in this post. In short, prediction errors happen when the clients prediction position is different from the servers position response, these errors are rare.

All these two commands do is tell the client how to 'react' to the error by smoothing the view over a certain amount of seconds (the clients perspective technically can be subtly inaccurate based on cl_smoothtime) or not smoothing it at all (will appear like a jump/teleport when corrected).


 While cl_smooth 0 is technically more accurate, prediction errors are rare. I'd perhaps lower the cl_smoothtime to 0.01 if you have cl_smooth enabled (default) but in the end it really doesn't matter much if you're playing in a good server. :-)