Ok, here's a more complicated question.
I have two 3D points which I have to "connect" with a rectangle.. sort of what I'd do drawing a LPD3DXLINE between them, however it needs to be a 3D mesh (i.e. perspective and distance resize it). The thing is, it also needs to bill-board itself towards the camera, and here I really don't know how to do it..
I could build a sin/cosine function that rotates 4 points around 2 vectors given a width, that's easy.. but how do I take care of the bill-boarding too?
I really don't have a clue about this one..
EDIT: here's an image as example...