Stl facets

I’ve been building some small components for machining on a 3D router. I’ve been outputting quite high quality files, which leads to quite large file sizes.

As a brief aside, I’ve seen that stl output is not recommended here, however I have no option, that’s the format my machine uses and no other.

My question is- when exporting to stl, the default option shows a medium quality file- how many facets might be used to describe the surface of a cylinder with this option? And how many facets in the high quality files I’ve been saving?

There must be a huge number, the lines show as solid black on the programs I can use to view them.

I suppose I’m looking for an optimal setting, through some understanding of how much the cylinder might be faceted at different settings

Thank you

I use Shapr3D STL files for all my 3D printing. Zero issues. I use Shapr3D DXF files for my waterjet, and laser CNCs. For DXF to my CNC machines, I just use the Top view. Otherwise, no issues.

Hi @jb7, the default setting for STL export is high quality, but you can always set the tolerance of the CAD-mesh conversion by switching the toggle to the rightmost, Custom Settings position. There you can set the deviation that is allowed at the end of the conversion.
By default, the goal is to export a mesh file with the least possible data loss, which results in quite small mesh polygons.

If you have a mesh viewer (like Meshmixer), you can always check the number of vertices and polygons, however, it is not possible in Shapr3D. For reviewing the file in your chosen software, please set the edges not to be shown.

ps.: mesh resolution cannot be set on Windows yet, we are working on it.

Thank you- I’m going to have to experiment with different settings, but it’s good to know that the stl export can be of very high quality-

It sounds like you are 3D milling and not just 2D cutting like flat plates on water jet, cnc router, plasma or laser cutter, which would be DXF in most cases. If the software you’re using to run the CNC only uses STL files, then an alternative could be using different software to generate the G code. I would look into the free version of Autodesk Fusion 360 for instance. The CAM functions are pretty amazing and should run your machine without too much trouble and with no facets. @jb7

I use Shapr3D to create STL files, which I import into Aspire, for use on my 3D CNC router. Aspire generates the G code for the router however.

I can see how STL files would be great for 3D printing, especially for smaller objects, or 3D milling of an object with lots of texture from a scan, but since exported STL files are no longer solid NURBs from Shapr3D and are lots of little triangles, it doesn’t seem like you would get as good of a milling strategy in most cases when the object starts out super clean and geometric in Shapr3D. It’s like rasterizing a vector graphic.

Thank you- yes, I use stl for my cam program, it’s all it it’ll take. Most of the things I produce are 3d, so I was just making an enquiry about the minimum level of detail to produce a good stl file. It looks like it produces very smooth surfaces at the expense of very large files; I’m going to have to experiment to find the optimum settings for different component sizes.

Obviously more facets will produce smoother surfaces, but that might only be necessary for larger items.

Yes, there are better strategies for milling, but everything takes time, and the priority right now is producing stuff, so I may not be in a position to invest time in learning fusion360- and last year I heard they were removing some functionality from the free version anyway-

Thank you for your replies-