# LinuxCNC G5.3

Instructions · `G5.3` · verification: source checked

G5.3 is the LinuxCNC G-code that closes a NURBS data block. It is programmed on its own line after a G5.2 block, and the lines between G5.2 and G5.3 define the curve control points together with their weights (P) and the parameter L that sets the curve order. G5.3 takes no axis words or other arguments.

## Specification

| Property | Value |
|---|---|
| Language | gcode |
| Code | G5.3 |
| Group | NURBS block |
| Syntax | G5.3 |
| Dialect | LinuxCNC |

## Safety

- G5.2 and G5.3 are documented as experimental and not fully tested.

## Study notes

- G5.2 opens the NURBS data block and G5.3 closes it; the control points are written on the lines between the two codes.
- Each control point line can carry a weight P and the parameter L, which determines the order of the curve.
- The current coordinate before the first G5.2 command is always taken as the first NURBS control point.
- Default weight is 1 when P is unspecified; default order is 3 when L is unspecified.
- The NURBS block section gives a G0/F10/G5.2 ... G5.3 example followed by an M2 program end.

## Sources

1. [G-Codes](https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g5.2-g5.3) (accessed 2026-10-26)

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Source page: https://machineschema.com/instruction/gcode-g05-3  
JSON: https://machineschema.com/instruction/gcode-g05-3.json  
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite Machine Schema and the original sources.