I've gone into some trouble understanding how the ray shoot out and the size relationship between the high and low poly mesh, below is my understanding,
But which one is right? From the menual it says the ray is generated from the low poly inwards to the high poly, then I suppose the first illustration is not right, because it points outwards.
The second illustration, the middle section should been working properly, but the left and right section has no high poly surfaces to point to, because it is starting point is inside the high poly, I searched and found someone says I can set the ray distance, then setting the distance won't change where the starting point the ray started, am I right?
The last one is I think how it should work, by having the low poly encapsulating the high poly, but I still needs some basic understanding how blender works with Normal map baking, thanks!
Edit:It turns out the ray will travel in both direction as opposed to what the Doc. says towards inwards.
The above shows the low poly has a cube inside and sphere outside, both have been reflected on the low poly cube.