Mooselake wrote:cacb wrote:The interesting part is that if we had a better format available, with explicit manifold or non-manifold topology, it would also be a much better basis than STL for printing multi-color prints from the same file.

Well, there's AMF - but that just looks like stl with XML and curvy triangles from a quick google search. Kirk

Although AMF isn't the ultimate format, there is more to AMF than what most people recognise immediately. STL has zero topology, nothing is really connected, everything must be inferred from coordinates. In AMF it is different, the vertices may be mentioned exactly once and the faces refer to the vertices. I.e. you have a basic topological model. That makes it possible to describe things you cannot describe with STL and the model can be interpreted exactly, without having to evaluate coordinates. AMF would therefore be much better suited than STL as a format for intermediate storage (re. the topic of this thread) or model exchange between different programs.

I have worked with meshes in other areas (Finite Element Analysis), and the way AMF does it is the conventional way to describe a mesh, even though that too is very much simplified.

With STL it is assumed you describe only the outer surface of the thing you have modelled. Such a model is called manifold, i.e. exactly 2 faces will share each edge, and each face has material on one side (inside) and no material on the other side (outside). However, it is useful to also consider non-manifold models, where some faces have material on both sides. Such faces are internal to the model, and could for example describe the internal boundary between two colors. You could do this with AMF, but not with STL.

So if AMF or something equivalent to it could replace STL, it would be a good thing.