I'm going to have Shapeways make a replacement plastic protective tip for on the end of my umbrella. Which plastic would be the best choice? Ideally it would be some thing very impact resistant, since thiskohi click test tip will be be hitting the ground a lot. My current one sort of exploded when it hit the ground just right, after many years of service. In the perfect world, it would be black, but I'm OK with other colors if need be. Lastly, would I get a better finished product with the more faceted shape shown in the attached sketch, or the more contoured? Ignore the proportions, as this is just a quick 1 min MS Paint sketch...I'm more curious if the inward click speed test and outward angles with flat sides would get a better end result, or eliminating one of the angles with a curve would.