How G-code preview works after slicing

After a successful slice, the Cloud Slicer can show a browser-based G-code preview. This helps you inspect the generated toolpaths before downloading, saving, queueing, or printing the file.

What the preview shows

The preview renders the generated G-code from the slicer engine. It is meant to help you inspect the output before sending it to a printer.

Depending on the file and engine data, the preview can show:

• Layer ranges
• Extrusion paths
• Travel moves
• Line types
• Extruder colors
• Speed colors
• Fan speed colors
• Seams
• Basic print information, when available

How the preview is prepared

After slicing finishes, SimplyPrint downloads the generated result file and prepares the preview in your browser.

The browser then parses the G-code, analyzes paths, and builds the preview geometry. Large files can take longer because the browser has to process many layers and paths.

Use the layer selector

Use the layer selector to move through the print or limit the visible layer range.

This is useful when checking:

• First layers
• Top layers
• Support areas
• Internal infill
• Tall sections of a print
• A layer where you expect a pause

Change preview coloring

Open the preview controls to change how the G-code is colored.

Current preview modes include:

• Line type
• Extruder
• Speed
• Fan speed

In line type mode, you can toggle individual path types on and off. Travel moves may be available as a separate line type.

Print information

The Print info panel can show analyzed information about the sliced file when that data is available from the slicer result and SimplyPrint analysis.

The exact values depend on the generated file and the analysis data available for that slice.

When the preview is outdated

If you change the model, plate, printer, or settings after slicing, the existing preview may no longer match the current setup.

When SimplyPrint detects this, it can show a warning that the G-code preview is outdated and offer to re-slice.

If preview is disabled or crashes

G-code preview runs in your browser. Very large or complex files can use a lot of browser memory.

If preview is disabled on your device, the slicer can still complete the slice and show output actions. You can preview only the current file, turn preview back on for the device, or continue without preview.

If the previous preview attempt appears to have crashed the page, SimplyPrint can warn you and offer to disable preview on that device.

Related articles

• How to slice, preview, download, and send sliced files
• G-code preview causing browser crashes or freezing
• How to download, queue, direct print, or multi-print sliced output
• Cloud Slicer troubleshooting overview

Updated on: 26/05/2026