Skeinforge Quicktip: Fill

Fill is a script that handles the interior of a given layer sliced by the carve script.  Objects can be made hollow or filled, or as is most common, somewhere in between.  For these hybrid cases, wall thickness can be adjusted, as well as the density of the internal threading to trade off between speed and strength or between strength and plastic used.

The Extra Shells options create additional lines which trace the outline of each layer, just inside the outer one.  I was never sure which layers were which between “alternating solid layers”, “base layers”, and “sparse layers”, so I keep them at the same value.  Extra layers aren’t necessary for all cases, and in especially light builds, they can be left at zero to print only the outermost layer as a solid line, with the interior of each layer printing only as sparse or nonexistent infill.  (Such builds can be prone to collapse during printing or fragile though!)  Cranking this up to three or so is important to getting good water-tight seals.

Infill options: inside each layer, skeinforge lays down a pattern of lines to fill in the interior of a model with strands of plastic, which may be very light or very dense depending on the settings.  Dense models of course are heavier, sturdier, and take longer and use more plastic.  The Infill solidity ratio is the ratio between the infill pattern and a fully-solid object.  Set to 1, this would solidly fill the inside of the object completely.  I’ve had trouble with setting it to zero for fully-empty builds, so when I want empty builds I just set it to 0.01 or such, which is fairly negligible in terms of plastic inside.  A value of 0.3 or so is pretty good for large, sturdy builds.  The infill odd layer extra rotation rotates the infill pattern every other layer, which at 90 degrees creates a square pattern if line fill is used.

I think the interior infill density ratio is a feedrate setting which moves the print head faster during infill pattern drawing to get lighter strands than the outer wall.  Anyone got a better definition?

The solid surface thickness is similar to the extra shells settings, but for horizontal layers.  Skeinforge makes this distinction because it’s different to have a solid fill pattern than to trace an outline.  This setting should be the same as the extra shells settings for builds with uniform thickness on all surfaces, like dice.  Also, low values for this may result in builds with tops that don’t close up fully (because the fill on the top layers sag into the sparse infill) or bottoms that aren’t fully watertight.