I've been planning to create a master for a set of resin casts (I actually need 12), which I'd like to create from a Shapeways original. Which raises 2 questions: 1) Which is the best material for making a casting? 2) Should I create a "positive" (i.e. the shape I want) or a "negative" (the mold)? Obviously it would save a step to directly create the mold, and I can't see any reason why that wouldn't work, since it's just as easy to create a concave shape as a convex one with this technique. But I haven't done this before, so perhaps there's a reason I'm overlooking. I'm planning for this to be a single-sided pour mold (simplest kind). This makes sense since the object is essentially a decorative cabinet handle, and the back can simply be flat. (more or less). A core will be suspended in the casting to form the back part of the handle with the threaded part. Any other considerations from anyone else who's tried this would be welcome too.