Originally Posted by VinceField

It would seem that lucid dreams are mental projections into the larger system of nonphysical reality which is connected with the physical dimension like a gradient, a full spectrum of energetic systems of different frequencies.

Lucid dreams are actually very similar to astral projections, the main difference being the reference point of one's consciousness- LD consciousness being from the vantage point of the mental body, and AP consciousness being from the vantage point of the astral body. These different energy bodies are likewise connected to one another in a gradient, the mental body being of a higher frequency than the astral body (although these two classes of bodies exist in a gradient of vibrational rates as well, ie lower astral body, higher astral body, etc), with the physical body being the base of the gradient.

Many experiences, whether classified as a LD/OBE/AP, actually contain a combination of aspects of these different bodies and dimensional levels, and it common for an AP experience to shift to a LD experience and visa versa, so classifying them is not always an easy task, although I don't believe it is all that important to do so. What is important is what one does with the experience. You can use these abilities to goof around and fulfill the ego's sensual desires, or you can use them for personal growth and the attainment of spiritual knowledge and insight.