FreeCAD Forum

Hi there!
From my research, STEP files are for CNC and there are two STEP formats offered in FreeCAD export
1. with colour
2. zip file
What is the difference between these two?
Sorry if this has been discussed but I couldn't find related information (and I can't use the searching feature with these words "step, file, export")

I don't need colour for my model,
so I shoud use zip?

Zip is a compressed step format.

The export process will not add color. Use whichever format works for your CNC application.

Gene

chrisb wrote: ↑Sat Mar 12, 2022 2:00 pm Zip is a compressed step format.

If I decompress it, will the file be the same as the "colour" one?

GeneFC wrote: ↑Sat Mar 12, 2022 2:40 pm The export process will not add color. Use whichever format works for your CNC application.

Ok so what are their differences?

fcbuilder wrote: ↑Sat Mar 12, 2022 4:30 pm If I decompress it, will the file be the same as the "colour" one?

I don't know, but its worth a try. The export function can be used at no additional cost.

The truth is STEP file format is not a CNC file type in and of itself, no more than IGES or DXF. These are just different ways of holding data in what we call a file type. You don't need a CAD or CAD / CAM program to view the contents of the file types. STEP files are interesting when you open them in a text editor and can be totally created in Notepad if you know how to organize the data. This is of little use for the average person and so we use other programs to display the contents of the file in a more meaningful way. Most of the people I know using plasma tables have never seen or used a STEP file to run their CNC because everything they cut is 2D and only requires a DXF file for them to get accomplished what they need to. Unlike the IGES file type (obsolete) the STEP file is still being maintained. It is like an open source file type that all good CAD / CAM programs should have no issue opening unlike the proprietary file types that are out there. If i save a solid model in MasterCAM as a STEP I have no issue opening it with FreeCAD but I cannot open the file type that MasterCAM saves in natively with FreeCAD which uses the .mcam file extension to designate that it is a Mastercam saved file.

chrisb wrote: ↑Sat Mar 12, 2022 4:37 pm

fcbuilder wrote: ↑Sat Mar 12, 2022 4:30 pm If I decompress it, will the file be the same as the "colour" one?

I don't know, but its worth a try. The export function can be used at no additional cost.

My bad for not explaining why I asked that. (I tried before asking)
My 0.19 FreeCAD can export STEP files but when I opened the zip ones, no model was displayed, and most of the colour ones broke...
So if I go to CNC with the zip files without checking them, it would be pretty risky. That's why I asked that

CoderMusashi wrote: ↑Mon Mar 14, 2022 9:37 am The truth is STEP file format is not a CNC file type in and of itself, no more than IGES or DXF.

Thanks for your detailed explanation!

Off topic but if I may ask, which format would you recommend for CNC? STEP or IGES?
I heard that some suggest avoid IGES, but with my current version of FreeCAD, IGES is the stable export format for me

fcbuilder wrote: ↑Fri Mar 18, 2022 10:18 am Off topic but if I may ask, which format would you recommend for CNC? STEP or IGES?

I would always go for STEP. That's what some of the shops acepted which I have tried so far. I think STEP export has been fixed in the latest 0.19 revisions, and 0.20 will become stable very soon, so I recommend to upgrade to 0.20 right away.

It’s Time to Get Over IGES (from GrabCAD Blog)
https://blog.grabcad.com/blog/2014/10/14/get-over-iges/