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G2-G3 - Arc or Circle Move

1.0.0-beta motion Add an arc or circle movement to the planner ARC_SUPPORT


G2 adds a clockwise arc move to the planner; G3 adds a counter-clockwise arc. An arc move starts at the current position and ends at the given XYZ, pivoting around a center-point offset given by I and J or R.

CNC_WORKSPACE_PLANES allows G2/G3 to operate in the selected XY, ZX, or YZ workspace plane.

This command has two forms:

I J Form

  • I specifies an X offset. J specifies a Y offset.
  • At least one of the I J parameters is required.
  • X and Y can be omitted to do a complete circle.
  • The given X Y is not error-checked. The arc ends based on the angle of the destination.
  • Mixing I or J with R will throw an error.

R Form

  • R specifies the radius. X or Y is required.
  • Omitting both X and Y will throw an error.
  • X or Y must differ from the current XY position.
  • Mixing R with I or J will throw an error.

Arc moves actually generate several short straight-line moves, the length of which are determined by the configuration option MM_PER_ARC_SEGMENT (default 1mm). Any change in the Z position is linearly interpolated over the whole arc.

‘ARC_P_CIRCLES’ enables the use of the ‘P’ parameter to specify complete circles


G2 [E<pos>] [F<rate>] I<offset> J<offset> [P<count>] R<radius> [S<power>] [X<pos>] [Y<pos>] [Z<pos>]
G3 [E<pos>] [F<rate>] I<offset> J<offset> [P<count>] R<radius> [S<power>] [X<pos>] [Y<pos>] [Z<pos>]



The amount to extrude between the start point and end point


The maximum rate of the move between the start and end point


An offset from the current X position to use as the arc center


An offset from the current Y position to use as the arc center


Specify complete circles. (Requires ARC_P_CIRCLES)


A radius from the current XY position to use as the arc center

[S<power>] 2.0.8

Set the Laser power for the move.


A coordinate on the X axis


A coordinate on the Y axis


A coordinate on the Z axis