From Hammond Deggs Music:
his user oscillator allows you to smoothly transition from triangle, to sawtooth, and through 0 to 100% pulsewidth pulse.

In addition, you can choose to modulate the shape via an internal LFO, or the external synthesizer LFO, plus you can apply an envelope to the shape.

Shape
Sets the base oscillator shape. This smoothly changes from triangle to sawtooth, and then through a 0% to 100% pulse. If you mix a bit of triangle with sawtooth you can approximate a 'shark tooth' type sound.

Shift+Shape
Sets the amount to apply the internal LFO to the shape. If this is set to 0, then you can use the external common LFO to modulate the shape. Note, settings the INT LFO rate to '1' (minimum) disables the internal LFO, so if you really just want a fixed waveform, set shift+shape to something other than 0, and set the INT LFO to it's minimum value (1).

Parameters

INT LFO Rate:
Sets the frequency of the internal triangle LFO from 0 Hz to 10 Hz. Note! Setting this value to it's minimum (1) not only stops this LFO, but 'disconnects' it. This way you can have a truly 'fixed' waveshape by setting this value to "1" and setting the shift+shape parameter to anything but 0.

Attack:
Sets the attack time for the shape envelope generator.

Decay:
Sets the decay time for the shape envelope generator.

Sustain:
Sets the sustain level for the shape envelope generator.

Release:
Sets the release rate for the shape envelope generator

EG Amt:
Sets the amount to apply the envelope to the shape parameter. This can be adjusted from -100% for an inverted envelope to +100%

Click Here for More Info from Hammond Deggs Music