All faces selection in Path (3D Pocket)

[DirkM]

Hi,

I am trying to mill an object from a stl-file. But it seems that I have found no suitable workflow for this. In the end the path is wrong - see attached picture. The actual object has round about 5000 faces.

I have had a success with a test structure made directly in FreeCAD and selected the faces --> ok
But a STL-file has thousands (or more) of faces. I have found no solution for this, because the "3D Pocket" accepts only faces. And clicking them one by one is no solution for me .

I have already tried:
1. STL to shape --> to solid --> no
2. trying to merge faces --> no
3. trying to use a macro to select all faces --> no (https://forum.freecadweb.org/viewtopic. ... 6&start=10 .. I stopped the macro after 30 minutes. Works fine with several 10 faces)

I think the main problem is the huge number of faces. If there is a solution for this I would be glad.

Thanks in advance.

Dirk




PS: I am using FreeCAD 0.19

[oeliks]

3D surface?

[chrisb]

1. STL to shape --> to solid --> no

What does this mean? Did the conversion fail?

[DirkM]

Hi,

@oeliks: This is the problem. You have manually click all surfaces. Does not work for an STL model with thousands of faces...
@chrisb: the conversion to solid works, but 3D Pocket can only work with surfaces (you can click them one be one on the solid, but this is not a solution).

Hope anybody has a solution .

Best

Dirk

[jbraun]

I don't have a solution but I am curious how many axis your machine has.
Honestly I'm not convinced FreeCAD is capable of milling that but would be very pleased to be proven wrong.
Possibly I don't know what I'm looking at but it appears to be a surface job rather than a pocket job.

[chrisb]

If you make a slight cut at the bottom, so that you get an easily deselectable face, then you can try the following:
- select "Set colors" from the object's context menu
- use box selection to select the faces. It is not quite clear to me how this box selection works, you don't have to cover all of a face, but too little doesn't work either.
- in case the bottom was selected too, deselect it using control key to keep the rest
- cancel the color selection => the faces are still selected
- invoke 3D surface => the faces are taken as BaseGeometry

And like jbraun I am interested if and how it works out with the overhangs, please report back.

[chrisb]

Here is a post talking about reducing the number of triangles with an external tool. You may have to do a bit more sanding, but that's probably still better than work it manually out of a block .

[Steveco]

When I use the "3D Surface" operation, if I don't select any faces, it defaults to the entire model. On a shape like the one in your screenshot, it's often necessary to uncheck "Boundary Enforcement" checkbox to get toolpaths that go down over the sides.

OS: Ubuntu 16.04.7 LTS (Trinity/trinity)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.23074 (Git) AppImage
Build type: Release
Branch: master
Hash: 74b866ed3022fd1452c534dae31a721bcc668f2f
Python version: 3.8.6
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

[DirkM]

Hi,

I testet again a lot of possibilities - see below. Thanks to you I solved this task!

I have simply overseen, that for "3D-Surface" you have to enable experimental features for the path workbench. So in the end I was stuck with "Pocket 3D" and the other unsuited tools.

Thanks to you all for your great help!

Best

Dirk

OLD
@chrisb: I tested this with a small area (350 faces). If I am going with the selected faces into 3D surface you have to wait a couple of minutes. After this I could set up milling operations. I testet with "Pocket_3D" and "MillFace"--> this was really the best idea so far (=selecting faces) but does not work. The tool does not follow the surface - see picture attached.

I uploaded the FreeCAD file, so you could test for yourself. I testes this with a 3 mm miller.

PS: @jbraun: I will test only three axis at this time. Next time hopefully 4 axis .

[chrisb]

No FreeCAD file attached.