I have my particles(via expression)parented to a position path in 3D space. So, what I want is the emitter to start in front of my host, travel along them, and then curl around and go behind. I've created the correct path with a simple solid, but that solid has 3 dimensions, so If I parent the position to the 3D Layer, the curve is correct, but the particles are always behind or in front of my people. I tried the obscuration layer, but this doesn't seem to help, as if I move the position of my 3D layer, the particles are either in front, or behind. I want them to start in front then as the emitter moves along the path go behind. Is this possible?