0001304: Allow Sketcher to Fillet Arcs, Not Only Lines

[abdullah]

In your sketch, there is a "missing" coincidence between the line and the ellipse.

Your are perfectely right, the right coincident constraint was missing. I'm sorry, I hadn't seen that.

I have retried the construction several time. When the line is drawn, the fix point on object constraints are set on both ends. When I now trim the ellipse, the first time the fix point on object is converted to a coincident constriant. On the second trim, the fix point on object is just removed, but no coincident constraint is placed.
SketcherTrimConeLineIssue.gif

you just discovered a bug from 2014... let me step on it:
git commit 92e68e2c3a742f49654871223fde8b0934f58b94

[RogerK]

Hi abdullah

you just discovered a bug from 2014... let me step on it:
git commit 92e68e2c3a742f49654871223fde8b0934f58b94

I can confirm with the current build 15150 the trim bug is solved. But unfortunately, there is another bug . When I trim first the right part of the ellipse, then the line looks like it was deleted too and the fix point on object constraint remain. A closer look reveals something different. The Line and ellipse segment is still there, but it was collapsed to one point:

SketcherTrimEllipseLineIssue2.gif (245.34 KiB) Viewed 435 times

Kind regards

Roger

[abdullah]

But unfortunately, there is another bug .

Yup! You are getting proficient a unveiling long introduced bugs.

If you want to see something funny, just delete the line, and trace a new line from right to left (roughly same positions), now trimming the right part works, but if you trim the left part instead, the line "jumps".

I know where the bug is, I have to find a solution...

[abdullah]

But unfortunately, there is another bug .

Only to note that it is a general bug of the trim tool, it also happens for circles:

Circle.gif (49.77 KiB) Viewed 406 times

[abdullah]

https://github.com/FreeCAD/FreeCAD/pull/1784

There were problems with some constraints (internal alignment) and with multiple intersections among trimming curves.

Trim_Improvements.gif (342.41 KiB) Viewed 385 times

[abdullah]

I forgot to say. I have made the trim tool a little bit more picky, because sometimes it was creating invalid coincident constraints. If you happen to get an exception and the result "undo", file a bug report and/or ping me. There may still be more trimming bugs in the wild.

[abdullah]

It is merged and in the PPA (thanks sgrogan!). I will appreciate some testing of this trimming functionality.

[RogerK]

Hi abdullah

It is merged and in the PPA (thanks sgrogan!). I will appreciate some testing of this trimming functionality.

I did some more testing with the fillet and trim functionallity.

One Issue I found was regarding filleting two arcs. When you click near the center of the arc's notthing happend. I guess this is because the algorythm couldn't found a proper solution for filleting the two arcs. When I click on the right side, it works, but the fillet is placed in the wrong direction and the arcs are shorten way to mutch:

SketcherFilletArcArcIssue.gif (126.11 KiB) Viewed 339 times

Testfile:

SketcherFilletArcArc.FCStd

(9.27 KiB) Downloaded 8 times

When testing the trim function I noticed that the hyperbola and parabola are not supported. You always get a forbidden/blocked sign when you want select them. Filleting on them works fine in my test cases, except in a similar setup like the issue described above, it could happen that the fillet won't work either between an arc and a parabola. Do you want a Testcase for this too? I hope I can repeat it, it won't always happend, its somehow depending on the geometry .

FreeCAD Version:
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15184 (Git)
Build type: Release
Branch: master
Hash: 9e2acc477cc8806f5b7ff13160f40c207a82aa50
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Switzerland (de_CH)


Kind regards

Roger

[RogerK]

I forgot to say. I have made the trim tool a little bit more picky, because sometimes it was creating invalid coincident constraints. If you happen to get an exception and the result "undo", file a bug report and/or ping me.

When this happend, is there an error message in the python console? Or hasn't the user any indication of this, from his perspective just nothing happend?
I had noticed multiple times where a trim doesn't changed anything, but in this cases also a delete of the segmet was possible. Maybe this is an intendet behavior because you wouldn't trim anything, you would just delete the clicked segement.

[abdullah]

I forgot to say. I have made the trim tool a little bit more picky, because sometimes it was creating invalid coincident constraints. If you happen to get an exception and the result "undo", file a bug report and/or ping me.

When this happend, is there an error message in the python console? Or hasn't the user any indication of this, from his perspective just nothing happend?
I had noticed multiple times where a trim doesn't changed anything, but in this cases also a delete of the segmet was possible. Maybe this is an intendet behavior because you wouldn't trim anything, you would just delete the clicked segement.

Whenever a problem trimming or filleting ensues, you get either an exception or a fail message. Something like this in the "Report View":

Exception (Mon Nov 12 13:39:03 2018): Not able to fillet curves with ids : (0, 1) and points (77.5314, 12.4934, 0) & (64.1419, -20.637, 0) In PyObject* Sketcher::SketchObjectPy::fillet(PyObject*) in src/Mod/Sketcher/App/SketchObjectPyImp.cpp:914

Failed to trim edge: Not able to trim curve with the given index: 2