I built a cat feeder using kitlaan's design (http://www.thingiverse.com/thing:27854) and I needed a slide for food. I modeled the slide to be extra long (3") so there is plenty of distance between the feeder and the food dish.
Spout / Slide is designed to fit right below a standard 2" PVC pipe and could be glued or screwed into place.
Created in Sketchup. No need for rafts or supports. I used 15% infill but would work fine with 10%.