==Trajectory Planner Arc Faceting and Colinear Collinear Tolerance==The Trajectory Planner works to simplify and smooth GCode by combining Linear and Arc segments into single Linear segments whenever possible if the resulting Linear segment will not deviate from the original path by more than the allowed Colinear Collinear Tolerance. [http://dynomotion.com/Help/KMotionCNC/ToolSetupScreenTP.htm#Trajectory_Planner See also here].
Note that arcs that require a long time (relative to Lookahead buffering time) to execute (based on arc length and feed rate) are subdivided into smaller arcs to avoid excessive buffering. If these arcs were not subdivided then on-the-fly Feed Rate Overrides (Software) could be delayed by long periods of time. If the resulting arcs are essentially straight lines (relative to the allowed Colinear Collinear Tolerance) then they will be treated as straight lines and may show faceting.
If faceting is a problem reduce the Colinear Collinear Tolerance to the level necessary for your system and requirements.
These arcs with a ColinearTol Collinear Tol of 0.0005 inches (12.7um) result in this faceted path (although not possible to see on this scale) that take about 12 seconds at the specified feedrate (much longer than the specified look ahead buffer time):
[[File:ArcsGCodeView.png|none|link=|753x539px]]
Expanding the Y Scale by about 13X allows the facets to be visible. The path deviations are approximately 0.0003inches (10um) which is less than the allowed (0.0005inches) 12.7um Colinear Collinear Tolerance.
[[File:ArcsTrajectoryZoomXTol.0005.png|none|link=|900x786px]]
Reducing the Colinear Collinear Tolerance to 0.0002inches (5um) eliminates the faceting
[[File:ArcsTrajectoryZoomXTol.0002.png|none|link=|901x787px]]