to DeskProto home page
looking glass icon
to DeskProto Facebook page
to DeskProto Youtube page
to DeskProto Instagram page

How to edit an STL file for CNC machining

Various Editing tools for STL files, both free and paid

As DeskProto works with STL files, for a DeskProto user it will sometimes be needed to edit an STL file.
This is not easy in case you do not have a 3D CAD program, and even if you have one: most CAD programs will become very slow or even crash after importing a 100 MB STL file (which is not even a very large one).
This page will teach you some tricks, and introduce a few programs that will come in handy for STL editing:

1. Use DeskProto

DeskProto Save-Geometry-As dialog
The DeskProto Save-Geometry-As option allows you to export a modified STL file.

The first trick is to use the tool that you already have: DeskProto.
DeskProto offers "Save geometry as..." (File menu), which allows you to include any of the transformations that you applied: scale, rotation, mirror and translation. You can also select the type of file (STL, DXF, WRL).
The Tips & Tricks page Positioning your geometry... gives a full explanation of this feature.

2. Use a special STL editing program

Logo for Magics, by Materialise
Logo for Geomagic, by 3D Systems
Two excellent commercial STL editing programs:
Magics by Materialise, and Geomagic by 3D Systems.

The most obvious solution is of course to use a special STL editing program. Several great programs are commercially available, offering a wealth of editing options.
For instance Magics by Materialise, and Geomagic by 3D Systems.
The downside is that these programs are rather expensive when compared to DeskProto.

MeshLab screenshot.
A powerful Open Source alternative is MeshLab, by the Visual Computing lab (ISTI institute) of the Italian National Research Council CNR. The illustration shows the 36 MB Coat-of-Arms STL file (a free download from this site), with only the knight's helmet selected.

Luckily for users on a tight budget an open source alternative is available: MeshLab, made by the Visual Computing lab of the "Institurto de Scienza e Tecnologie dell'Informatione".
The link above points to a free download (under de GPL license). We have successfully used it to edit some large STL files (for instance extract one small detail and save that as a new STL).

3. Use a CAD program

DeskProto screenshot of an STL file, before smoothing
DeskProto screenshot of an STL file, after smoothing
Same geometry, before and after smoothing the STL file in Cubify Sculpt, shown in DeskProto.

The next tip was emailed to us by DeskProto user CarveTech, who also sent the two pictures above from one of his recent projects (a set of "Basket weave" table legs).
The first STL file was made in CAD program Moi3D, and it was then smoothed in Cubify Sculpt (now also by 3D Systems). Both are lowcost programs. CarveTech tells about the smoothing: "The process in not for the faint of heart: it takes files from a few MB up to hundreds of MB !"

4. One more STL editing program

MeshMixer screenshot.
Meshmixer, by Autodesk.

CarveTech also uses MeshMixer by Autodesk, a free STL editing program.
The videos on the Meshmixer website show a set of quite powerful STL editing tools.