Am trying to create an effect in ae6 and particular where steam flows along cutaway top views of pipes. Is there a way for particles (coming from the same generating point) to change direction? As in turning left or right, down or up along the pipes?
Nope, not really. You can try to fake the effect for one turn using the Radial Field, but even then it doesn't look right. I'd say forget Particular and approach this another way. Get Digital Anarchy's Anarchy Toolbox with the Path Distort Tool, it will be much more useful in this case.