Mia culpa in the context of the above unfortunately true quote from HH Dudjom Rinpoche. (Now you know who I am, and who I am not)
All good posts in this thread, but hard to know where to start, so I am just diving in.
Great posts and each is correct from the posters’ point of view.
These things are really tricky to talk about - easy to be incomplete, but on balance, I think Futerko’s comment on the inseparability of the three bodies is a good place to start.
I think that the three bodies of the Buddha are three ways to talk about different aspects of how a Buddha manifests. Since we are not Buddhas (yet) we use these limited words and concepts to point to what is beyond our own experience, and beyond normal terms of expression.
I don't know scriptural citations, or have spiritual experience, but having listened to Dharma talks for a long time, words come out like wind blowing through a bamboo forest, makes sound. If you need citations, please look elsewhere. I apologize for not being a scholar.
The Nirmanakaya is the physical form of the Buddha, closest to what we refer to as the normal body. But it is different from the normal human body because it is entered into, and maintained, by enlightened intention - not by karmic forces. A Buddha has no need to be born into, or stay in, a human body. This is why it is always
a good idea to request our Teachers to remain. From their side, if they are real Teachers, they do not need to remain. You may wish to think about this and consider all of the great Masters whom you have met, or known to exist, during your lifetime, and who are no longer with us in their Nirmanakaya form. What can we do to help the Enlightened ones, who are still with us, to stay?
For the Sambogakaya, perhaps it is good to start by going to the wiki, because this will show how hard it is even for official sources to get it right.http://en.wikipedia.org/wiki/Sambhogak%C4%81ya
Here they are talking about the Sambogakaya as being a "subtle body of limitless form."
This is not my understanding. For me, the Sambogakaya is not a subtle body of limitless size. Maybe you can say that the Sambogakaya has the potential to manifest in infinite forms, and this rings true. So maybe they just left off the "s" off the word form. Perhaps the wiki is just not so useful. Enough about Wiki.
For me, the Sambogakaya can be spoken of as the energetic body. Sometimes it is called the "enjoyment body," I think, perhaps, because if you enjoy a lot, while in a certain state of contemplation, then this body may manifest. Also, it could also be considered enjoyable, because it is made of energy, and, since it is not physical, cannot be harmed by disease, fire, heat/cold, or death, etc. Sometimes it is called a body of light, because from the Buddha's point of view, I think that that is what it feels like and is perceived as.
Sometimes it is called the speech aspect, because speech can be considered the closest to a pure energy manifestation of the three ways of talking about existence as body, speech, and mind. I think it may be also sometimes useful to think of the Sambogakaya as a reification of idealized qualities, or embodying a certain collection of qualities, such as the "manifestation of the qualities of Vajrasattva." This does not define the Sambogakaya, but the Sambogakaya can lend its qualities to an idealized collection of qualities, such as Vajrasattva.
Hence, Vajrasattva, as a Sambogakaya form, can be thought of to intrinsically possess, and represent, a collection of idealized qualities.
The Sambogakaya may also be thought of as a possible bridge between the Nirmanakaya and the Dharmakaya, in both directions. Through strong intention, a Nirmanakaya, manifesting a Sambogakaya, while alive, or at the time of death, can transcend the death of the human body. Through strong intention, the body of light continues even after the death of the human body. In the same way, through continuity of intention, an un-embodied Sambogakaya can manifest an intentional rebirth as a Nirmanakaya when the opportunity presents itself. This explains the possibility of the continuation of consciousness across several lifetimes, such as in the case of Tulkus and the Dalai Lama. It also explains why Garab Dorje, the originator of Dzogchen, can be referred to as the Nirmanakaya of Vajrasattva, a Sambogakaya being.
Just as the Nirmanakaya, through contemplation, can generate a Sambogakaya, so the Sambogakaya, in contemplation, can become the Dharmakaya. In all these ways you can see how the Sambogakaya can be spoken of as a link between the Nirmanakaya and the Dharmakaya. Please to remember that talking about the qualities of the three bodies of the Buddha are really just ways of talking about the qualities of one Buddha.
I think that everyone has the potential to see, and to be in, the Sambogakaya, but only those who are sensible to this energy, actually see it, or can be in it. This capacity can be developed through spiritual practice. Perhaps when this capacity is accomplished, then it is easier to enter into the contemplative state of the Dharmakaya, which has no characteristics, or claims, whatsoever. Perhaps this could also be called creative visualization and absorption. This shift into a capacity for experiencing a different sensibility is what happens in the pointing out instruction and is strongly enabled by the Yangtig practices of the dark retreat, trek cho and togal.
The Dharmakaya is the manifestation of the Buddha, in pure form, without any named qualities whatsoever. It is the source from which all qualities manifest. This does not imply or necessitate, a causal relationship, but is just a way of talking about things from a certain point of view.
The rainbow body, (to keep on topic) as spoken of in Dzogchen, may display as a Nirmanakaya form, a Sambogakaya form, or both, at the same time. It somewhat depends on the capacity of the viewer. Someone who has obtained the rainbow Body may choose to continue on in their Nirmanakaya form, and normal people would see this. Their energetic, Sambogakaya form would be seen by those who have capacity to see it, both while they are alive and also after, if the Being with the Rainbow Body, makes the intention of keeping a manifested Sambogakaya form after death. When these forms completely dissolve into the Dharmakaya, then it is called the Great Transfer and nothing is left, and no one can see these forms.
Perhaps someone who is a Dzogchen Master, can, at will, dissolve their Nirmanakaya into their Sambogakaya, and also their Sambogakaya into the Dharmakaya. This explains why their appearance can alter during transmission.
Perhaps these questions are more appropriately asked of a real spiritual Teacher. I am just babbling.
Sorry if I have confused anyone.
Ask questions if you want to. Perseverance furthers!
Hope this helps.
Since these are just intellectual words that do not directly lead to experience, I do not put a heart here, just a
Long life to the Masters. May they live long, in good health and with success in all things.