Last Update: 16 December 2019

One last piece of the CNC toolchain which makes a nice addition is a visualization software. Visualizing a cutting path isn’t mandatory, but by doing so before actually running it on your LongMill it can help to verify that the machine is going to cut out your project in the way that you expect it. Some visualizers will show just the movements of the tool, but the better ones will actually simulate a 3D model of how the material will be cut away to make the final object.

In many cases, the CAM software you choose to use (and in some cases the interface software) will have visualization built-in. If you don’t have any visualization available to you in one of your existing software packages, you can either change one of your current software packages to one that does, or you can use a separate piece of software. These separate packages will normally allow you to directly import the generated g-code files from the CAM software and show you the simulation directly from that.

With all this being said, here’s our list of external visualizers which are available out there to use online or download. Please note that G-code Simulator and CAMotics are the only softwares which we’ve used extensively at this time, so please experiment with the other options out there at your own discretion:

Name Type Difficulty (1-4) Compatibility Starting Price (CAD) Free Trial Length
G-code Simulator Visualizer 1 Online Free
NC Viewer Visualizer 1 Online Free
CAMotics Vis / Int 2 Win/Mac/Lin Free
Discriminator Visualizer 2 Windows Free
NC Corrector Visualizer 2 Windows Free


G-Code Simulator

Allows for files to be drag-and-dropped right into the window or you can copy/paste the g-code in. Highlights tool movement based on the selected line, and provides cutting bounds and estimated cutting time for your file.

NC Viewer

Fast and easy to open and view files. Allows you to play the cutting path of the tool through 3D space.

CAMotics blank

Previously known as OpenSCAM, CAMotics simulates 3-axis g-code paths, shows 3D cutouts, simulates machine geometry, and is capable of connecting directly to the buildbotics controller. It’s also able to export the simulated cut workpiece as an STL and can add height probing to 2D g-code files.

Discriminator blank

Discriminator has more advanced tools for code editing, colouring, and code comparing. The visualization window is reasonable but a little tricky to use just like the rest of the software, and the software as a whole runs a little slowly, but otherwise it’s a resonable visualizer to use.

NC Corrector blank

Allows for easy line-by-line visualization, provides g-code statistics, g-code coulouring, path selection, and measurement between toolpaths. The primary downside is that the software runs quite slowly which makes it less user friendly.