What is it?
With the Clip Envelope you can control the clipping of a sound over time, and with the LFO you can modulate the amount of clipping with control of the depth over time.

How to use it
The Clip Envelope has the following two parameters, Range and LFO.  The default parameters will not do any clipping (after Reset).

The Range popup menu can have a value of x1 to ÷12, it controls the maximum amount of clipping the envelope can have when it is processed.

The LFO dialog box lets you modulate the clipping of the sound.  When a waveform is selected, the envelope controls the depth of the LFO.

Notes
Why would you want to use the Clip Envelope?  You can get some strange effects.  Try the Clip LFO on a sound that's made from a sine waveform.  As the the sine wave gets clipped, it turns into a square wave.  

See "Envelope", "LFO", and "Reset" for more information.