Please help to repair a step shell into a solid

[easyw-fc]

can Analysis Situs healing tools help in fixing some of this issues, for example removing the problematic wires from the top face?

Sorry, I am a bit lost in the topic. Can you provide the step file with the problematic wires? I will check if it is possible to remove them, and, if not, try to extend the software accordingly.

Is there a sort of 'defeaturing' for wires available for OCC?
Are you using your sw?
http://analysissitus.org/index.html

[saso]

Sorry, I am a bit lost in the topic. Can you provide the step file with the problematic wires? I will check if it is possible to remove them, and, if not, try to extend the software accordingly.

There are actually a few issues with this model and some of them I believe cannot be fixed automatically but need a manual reconstruction (in my previous post)... However, for example the top face has this issue with inner wires, this could be fixed with a healing/repair tool. I was actually already able to fix it but adding a tool for this also to Analysis Situs would be nice and of course also to FreeCAD . I was able to fix it in two ways (1) Salome has a tool to remove inner wires (2) with FreeCAD using Draft Downgrate tool -> result is individual wires from the face -> removing the inner wire and using Draft Upgrade to get new faces -> then using Part Cut to cut the inner faces from the main face... freecad-heini-1 also mentioned he was able to fix it in some way... ?

Attached topface.step is the problematic face with inner wires, RemoveIntWires_1.step is the result using the Salome Repair tool Suppress Internal Wires, FreeCAD downgrade-upgrade technique gives me basically the same result.

[easyw-fc]

RemoveIntWires_1.step is the result using the Salome Repair tool Suppress Internal Wires

the face seems to have a lot of geometric issues ... is there a way to fix them?
Are those real issues?
-

[freecad-heini-1]

RemoveIntWires_1.step is the result using the Salome Repair tool Suppress Internal Wires

the face seems to have a lot of geometric issues ... is there a way to fix them?
Are those real issues?
-

Yes, this is a real part of a customer designed in CimatronE 13.0, or maybe he received the data from another system. In tool and mould making this is unfortunately normal in everyday working life.

I repaired the top surface like this.
1. Surface Workbench, Extend Face, U=0, V=0
2. Lattice2 downgrade to wire,
3. Lattice2 explode compound
4. deleted the faulty inner curves
5. the remaining curves are combined in the Part WB to a compound
6. part WB symmetrically extruded on both sides as a surface
7. slice apart
8. the inner surface is repaired with it

[saso]

the face seems to have a lot of geometric issues ... is there a way to fix them?
Are those real issues?

What exactly the results of this additional checks mean I don't know, I guess it has to do with tolerances, there was a discussion about this before https://forum.freecadweb.org/viewtopic.php?t=26439

I did however a few more tests, with the FreeCAD Downgrade-Upgrade technique I get at first only one of this warnings about the edge, when I however export the surface to step and then import it back and run the tests again I get a lot. With the technique from freecad-heini-1, to extend and slice the face I get at first zero of this warnings, but when exporting it to step and importing it back I again get a few (but less then with the Downgrade-Upgrade technique or Salome). If we look at this with Analysis Situs we see that with Salome the reported Max tolerance is 0.033359407069762412, with the FC Downgrade-Upgrade it is 0.048368106859888467 and with freecad-heini-1 extend and slice technique it is just 0.0011572624325076714 however if we look at the shape properties (with Analysis Situs or FC Curves Geometry Info tool) we see that the Extend face tool creates a shape with a different properties CN 4x3.. then the original shape C2 3x3... while the other techniques keep the original properties (at least in this case). My understanding is that in general it is preferred to work with more simple surfaces and that this tolerances are acceptable and that all parametric cad system work with them and that how big the actual accepted tolerance is, is different from each case but, what exactly all of this means I also don't know

Attached are the two additional step files with exported top face fixed by the FC Downgrade-Upgrade and one following the steps by freecad-heini-1 with extending and slicing the face (this are additional to the step file provided in my previous post fixed with Salome)...

[Quaoar]

Is there a sort of 'defeaturing' for wires available for OCC?
Are you using your sw?

Yes and yes. As for defeaturing of wires, you can find the common tool in OpenCascade, which is the BRepTools_ReShape. It is not a true "defeaturing" utility though, just because it is incapable of rebuilding the geometric primitives (e.g., it cannot extend and reintersect faces). At the same time, it allows for the replacement and removal of topological entities in a shape. Actually, this tool can be seen as a groundwork of Euler operators. The principle behind is to rebuild a topology graph without even touching the geometry:



One can use BRepTools_ReShape to eliminate the internal wires from the problematic top face. I have been playing with that sort of functionality in Analysis Situs (though, without BRepTools_ReShape) and here is something I ended up with currently:

I was actually already able to fix it but adding a tool for this also to Analysis Situs would be nice and of course also to FreeCAD

Yes, thanks for the idea. You motivated me to reconsider a few things in the app As for FreeCAD, it should not be difficult to integrate BRepTools_ReShape, though one should be careful to not allow the user corrupt his shape (as it is very easy to do -).

[easyw-fc]

Yes and yes. As for defeaturing of wires, you can find the common tool in OpenCascade, which is the BRepTools_ReShape. It is not a true "defeaturing" utility though, just because it is incapable of rebuilding the geometric primitives (e.g., it cannot extend and reintersect faces).

Thanks

One can use BRepTools_ReShape to eliminate the internal wires from the problematic top face. I have been playing with that sort of functionality in Analysis Situs (though, without BRepTools_ReShape) and here is something I ended up with currently:
...

Great! I need to install your sw... very useful your gif to display the workflow... Thanks

As for FreeCAD, it should not be difficult to integrate BRepTools_ReShape, though one should be careful to not allow the user corrupt his shape (as it is very easy to do -).

Hummm ... I need to ping @Chris_G to see if he may be interested to add this too

Hi,
I am giving a try at implementing OCC Defeaturing.

[Quaoar]

I need to install your sw...

I still have to repack the installer to make this feature available. Will post here once done.

[freecad-heini-1]

Is there a sort of 'defeaturing' for wires available for OCC?
Are you using your sw?

Yes and yes. As for defeaturing of wires, you can find the common tool in OpenCascade, which is the BRepTools_ReShape. It is not a true "defeaturing" utility though, just because it is incapable of rebuilding the geometric primitives (e.g., it cannot extend and reintersect faces). At the same time, it allows for the replacement and removal of topological entities in a shape. Actually, this tool can be seen as a groundwork of Euler operators. The principle behind is to rebuild a topology graph without even touching the geometry:



One can use BRepTools_ReShape to eliminate the internal wires from the problematic top face. I have been playing with that sort of functionality in Analysis Situs (though, without BRepTools_ReShape) and here is something I ended up with currently:

I was actually already able to fix it but adding a tool for this also to Analysis Situs would be nice and of course also to FreeCAD

Yes, thanks for the idea. You motivated me to reconsider a few things in the app As for FreeCAD, it should not be difficult to integrate BRepTools_ReShape, though one should be careful to not allow the user corrupt his shape (as it is very easy to do -).

Hello Quaoar,
Thank you very much for your very good work.
Will there ever be a Linux version of Analysissitus?
Many greetings
Wilfried

[Quaoar]

Hello Quaoar,
Thank you very much for your very good work.
Will there ever be a Linux version of Analysissitus?
Many greetings
Wilfried

Hello Wilfried,

I am eager to have it but still cannot allocate enough time.

Kind regards,
Sergey.