1) There's no assignable LFOs in Rapture itself. The internal modulators are all pre-wired to specific destinations (pitch, cutoffs, etc.). It's been a feature request for "Rapture 2".
2) I've been pushing for the per-track arpeggiator to have a MIDI LFO mode for years now. But you can add a MIDI FX or VST that will do it (for free, or at a reasonable cost). Google MIDI LFO, MIDIShaper, etc. Cakewalk used to include SpectraFX, which would automatically draw automation in oscillator shapes. Frank's MIDI Plugins includes a Step plugin that will generate MIDI CC's that can be shaped & oscillated. There are others I'm not thinking of.
3) I rely on external hardware, for the most part. Moog discontinued a control pedal recently that sent MIDI LFO messages. I use my AKAI Max 49 step sequencer as an LFO. The Lexicon MPX-1 effects unit is an incredible source of MIDI control, including two LFO's.
In Sonar X2, you can try right-clicking on the draw tool, and select one of the alternate Shapes. You're having trouble with Freehand, but Sine, Square, Triangle, or Random might help with repeatable results. Use Snap to Grid and the related drawing commands. I've used this to draw oscillator "clips" at different rates, converted to MIDI CC and saved, then dragged out as a clip for as many repetitions as I need.
Of course, once you have the MIDI oscillator source in place, you'll have to assign it to Rapture's Smooth parameter. Either configure a slot in the Modulation Matrix, or use right-click / MIDI learn directly on the parameter. The range of Smoothing is 1-1000, but you'll find that it becomes more difficult to discern the differences above 100. You may only need to automate a much smaller range (1-50, or 1-100) for the results that you're after.
post edited by b rock - 2013/02/03 15:05:04