I’m trying to form a mental model of the slicing and printing process, and I have three initial questions:
1/3. Wall versus shell. These two terms mean different things, but usage seems to be split between (1) a wall being built of shells, and (2) a shell being built of walls. In both cases, skin seems to be consistently defined as the most exterior shell or wall. What are the canonical semantics for these terms?
2/3. Top and bottom versus wall. For some randomly shaped object, one would expect the entire thing to be enclosed in a wall (definition 1) or, if it has penetrating holes, a number of walls. Even the top and bottom rims of a vase should be a walls. Cura seems to implement walls layer by layer, rather than globally, so that non-vertical walls are be thinner than vertical walls. This in turn necessitates the treatment of the top and bottom as special (optional) things. Is there another slicer that takes a more rational approach?
3/3. Extrusion or “squishtrusion”? Where does the nozzle “fly” relative to the previous layer? If it is at a relative height greater than or equal to a nozzle diameter (and both are greater then the layer height), then the process is extrusion, wherein the molten filament is stretched to a thickness less than the nozzle diameter. In this case, the shape of the bead will be roughly circular. If it flies less than a nozzle diameter above, then the process is “squishtrusion” wherein the molten filament is compressed and dragged. In this case the shape of the bead will be wider than it is high, and its height will be the nozzle height. For extrusion there is no independent control of bead height and width. For “squishtrusion” there is some scope for independent control of these outcomes. So what is the normal relativity of nozzle size, nozzle height and bead thickness?
4/3. Is “bead” the right term?
Thanks in advance,
Neil
