DeskCNC surfacing efficiency was Re: Measuring accuracy

One thing that may also be of interest about the efficiency of
Stlwork and DeskCNC toolpaths, is that both programs use an algorithm
that we call tangency deviation. This is a setting under options in
both programs. In effect it looks at the upcoming toolpath moves and
if they are within the deviation setting, a single move is
substituted for a long series of nearly straight lines.

The defaults in DeskCNC are .002 for roughing and .001 for
finishing. This is in inches and if the programs are used in metric
units these settings should be adjusted by a scale factor of 25.4,
that is .050 for roughing, and .025 for finishing.

These settings have the effect of converting the long flat areas
around a model, or across a flat planar area, to a single G01 instead
of the hundreds of lines of code that would normally be generated
from each discrete triangle. On a controller with limited memory,
under DNC conditions, or on one which does not use continuous
contouring (like Turbo CNC or Ahha), this will speedup the processing
and also make the cutting much smoother, with a single ramp up and
down. It also reduces the size ( number of characters) in the
resulting G-code program. Note that this capability has been in
DeskCNC since it was released in 2002, and in StlWork for several
years before that.

Fred Smith - IMService
http://www.cadcamcadcam.com