Previewing G-Code

Note that some Communication / Control programs have previewing functionality built in.

Of especial note is https://github.com/grbl/grbl-sim which allows one to validate that Grbl will run a given G-code file.

In a class by itself is Forum user GrblGru's full 3 dimensional virtual machine simulation in software: GrblGru = Free 3D-Simulation for ShapeOko2 which provides a way to visually simulate a workflow from end-to-end w/o the need to have a physical machine. Please note that that link takes one to the first page of the discussion. There is additional information (and newer versions) in later posts. This has since expanded to include CAM functionality. https://www.grblgru.com/

Additional programs to consider

CNC Simulator

https://gcodetutor.com/

http://www.cs.technion.ac.il/~gershon/personal/NCSim/

https://ncviewer.com/ --- online (HTML5 / WebGL) gcode previewer

jViewer - The simple G-Code Viewer available from http://www.jtronics.de/forum/viewtopic.php?f=17&t=281

http://www.microtechstelladata.com/CncPlot.aspx

SnapCNC --- Google Drive Microsoft Store

https://github.com/arpruss/miscellaneous-scad/blob/master/scripts/gcode2scad.py --- "generates an OpenSCAD file which simulates the cut with an adjustable bit shape."