GCode Macros

Variable Substitutions and Expressions in GCode Macros

FDM (3D Printing) variable substitutions

All Modes "pre" and "post" (header/footer)

• {top} = offset in mm of bed top Y axis

• {left} = offset in mm of bed left X axis

• {right} = offset in mm of bed right X axis

• {bottom} = offset in mm of bed bottom Y axis

All Modes "post" (footer)

• {time} = job run time (printing/milling) in seconds (fractional)

• {print-time} = alias for {time} ... deprecated after 2.8

• {print_time} = alias for {time} ... 2.9 and beyond

3D printing / FDM mode only

"feature" macro only (as of 3.4)

• {feature} = feature region of the print (brims, infill, etc)

• {minx|miny|maxx|maxy} = position in mm of extents of the print area

"pre", "post", and other macros

• {temp} = hot end temperature

• {bed_temp} = bed temperature

• {fan_speed} = active cooling fan speed (usually 0-255)

• {material} = length in mm of material (filament) used

• {layers} = total # of layers

• {layer} = current layer number

• {height} = current layer height in mm

• {range(from,to)} = evaluated using {layer} and {layers}

• {pos_x} = last output X position

• {pos_y} = last output Y position

• {pos_z} = last output Z position

• {progress} = 0-100% state of print output

• {tool} | {nozzle} = current tool in use

• {tool_count} = number of tools used in print

• {tool_used_n} = whether tool # n is used in print

• {z_max} = max build height in mm

• {z} = current z position

• {e} = amount of filament extruded

Logical Code Flow (IF / ELIF / ELSE / END)

;; IF { layer >= 10 && layer <= 20 }
;; ..... inside 10-20 layer={layer}
;; ELIF { layer >= 15 && layer <= 25 }
;; ..... inside 15-25 layer={layer}
;; ELSE
;; ..... did not match previous tests layer={layer}
;; END

PREAMBLE control (v3.4+) allows for intro comment and config list to be re-positioned after the header or disabled. This was introduced to allow GCode output to work with Ultimaker.

;; PREAMBLE OFF

;; PREAMBLE END

Axis Remapping (v3.5+) allows for over-riding the default axis names. Useful for swapping axes and changing output for specific firmware targets. The format of the map is a JSON object.

;; AXISMAP {"X":"Y", "Y":"Z", "E":"E1"}

CAM Header Directives

Comments Rewrite (v3.8+) converts ; comments into () parenthesis format

;; COMMENT_REWRITE_PARENS

Minimize the size of GCode output (v3.8+)

;; COMPACT-OUTPUT

Set decimal precision (n = integer) (v3.8+)

;; DECIMALS = n

CAM variable substitutions

• {tool} = CAM tool #

• {tool_name} = CAM tool name

• {time} = dwell time in seconds

• {time_ms} = dwell time in milliseconds

• {time_sec} = dwell time in seconds

• {speed} = spindle speed

• {spindle}, {rpm} = spindle speed (v2.7+)

• {feed} = last output feed rate

• {pos_x} = last output X position

• {pos_y} = last output Y position

• {pos_z} = last output Z position

Axis Scaling (v3.7+) allows for a factor to be applied to X,Y,Z coordinates. Useful for some machines like the Roland MDX-40A that uses an unusual coordinate space. Default axis scale is 1

;; SCALE { "X":100, "Y":100, "Z":100 }

CAM & FDM : simple algebraic expression support

• Text inside {} is evaluated algebraically with access to JS classes and methods

• {Math.min(layer/layers, 0.5) + 1}

• {token+n} {token-n}