3-axis techniques that produce toolpaths in the principle planes can approximate them with 3D lines and arcs.
To activate this option, select Approximate linear moves with arcs and lines in the Output Options dialog in FeatureCAM.
To output the proper G-codes, the Post must support 3D arcs. The proper G-codes for each circular plane must be entered in the NC Codes dialog in XBUILD. These G-codes are stored in the <PLANE> reserved word. The Circular Move format must also be augmented to support arcs in each plane. The logical reserved words <XY-PLANE>, <ZX-PLANE>, and <YZ_PLANE> distinguish the plane of the current arc.
The following is an example of the Circular Move format for 3D arcs. The major purpose of the various cases is to output the correct arc centers.
{N<SEQ>}{<PLANE>}<MOTION>
<IF><XY-PLANE><THEN>
X<X-COORD>Y<Y-COORD>{Z<Z-COORD>}
I<X-CEN>J<Y-CEN>
<ENDIF>
<IF><ZX-PLANE><THEN>
Z<Z-COORD>X<X-COORD>{Y<Y-COORD>}
K<Z-CEN>I<X-CEN>
<ENDIF>
<IF><YZ-PLANE><THEN>
Y<Y-COORD>Z<Z-COORD>{X<X-COORD>}
J<Y-CEN>K<Z-CEN>
<ENDIF>
{F<FEED>}<EOB>