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G-code Viewer

Preview a sliced G-code file in 3D: layer by layer, coloured by feature, move type, speed or extruder.

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Click to browse or drag & drop files here

Select a G-code file

Accepted: .gcode,.gco,.g,.gc,.ngc,.nc,.txt

Files up to about 40 MB open comfortably. Everything is read in your browser — nothing is uploaded.view_in_arNo file open yetChoose a sliced .gcode file to see its toolpath in 3D.

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Look at the toolpath, not at the file

A sliced G-code file is a few hundred thousand lines of coordinates. Opening it in a text editor tells you nothing; re-opening the project in your slicer tells you what the slicer intended, which is not always what it wrote. This viewer draws the file itself — every G0, G1, G2 and G3 in it — so you can see the print the printer will actually make.

Drop in a .gcode, .gco or .g file. Nothing is uploaded: the file is read and drawn in your browser.

What you can do with it

  • Scrub through layers. Set a bottom and a top layer, or isolate a single one. Inside the top layer a second slider walks the print head move by move, the way the printer will run it — the fastest way to find where a feature actually gets laid down.
  • Colour by what matters. By feature (outer wall, inner wall, solid and sparse infill, top and bottom surfaces, bridges, support, skirt and brim), by move type, by speed, by layer, or by extruder on a multi-material file.
  • Show or hide travel moves and retractions. Travel is drawn dimmed and off by default; turning it on is how you diagnose stringing, and the retraction markers show where the filament was pulled back — including firmware retractions written as G10/G11, which have no move of their own.
  • See the build plate. The grid is taken from the file's own bed_shape or printable_area when it declares one, and sized around the print when it does not. The tool tells you which.

Feature colours depend on the slicer

Feature colouring reads the ;TYPE: and ; FEATURE: comments that PrusaSlicer, SuperSlicer, OrcaSlicer, Bambu Studio and Cura write. Some files — old Slic3r output, Simplify3D, machine-generated programs — carry none, and everything in them is shown as unclassified. That is the file's limitation, not a failure of the viewer.

About the time figure

The printing time shown is an estimate from a motion-planner model: junction speeds, acceleration and deceleration ramps, and the acceleration limits the program sets for itself. When the slicer wrote its own estimate into the file, that is shown next to it. Use the analyzer if you want to change the machine limits and see the estimate move.

Filament length comes straight from the E values in the file and matches what the slicer declares.