Fillet on inner corner issue

[TomD]

Hello,

After making a very small adjustment on a body (in Part Design), a fillet on an unrelated part of the body no longer was valid. I wonder why that is.
Edge 112 is the culprit.

I already ruled out:
- no additional faces were created
- making the fillet through a separate fillet didn't work

Perhaps
- the original was made in V0.18, the adjustment is done in V0.19
- something else behind the scenes in the FreeCAD engine I have to know about.

edit: I also noticed that the offending edge is called 'edge 112' when I select it within the original filled (Fillet_3mm), but that it gets named 'edge 48' when I select it within a separate fillet. It might be another topological naming issue?

Both projects included.

OS: Windows 7 Version 6.1 (Build 7601: SP 1)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: Dutch/Belgium (nl_BE)

[drmacro]

I'm not at a pc so I can't actually look at the file. But sounds like TNP.

You could review your model based on some of the suggestions here: https://wiki.freecadweb.org/Feature_edi ... ble_models

[TomD]

Yes, i thought it might. The edge gets the name 112 when I select it within the original group fillet, but FreeCAD gives it a different name (edge 48) when I select it separately.

[Shalmeneser]

You should set Refine=True in the last Pad, before filleting.

[TomD]

You should set Refine=True in the last Pad, before filleting.

thank you, most helpful!

I am not yet aware of this option. Where can I find it?

What does this refine = true and why is it necessary in this case? Or should I always use it?

edit: found this topic:

https://forum.freecadweb.org/viewtopic.php?t=53204

• The Refine option is difficult to discover by a new user. The default should therefore tend to the needs of new users.

• Other CAD systems behave in a way consistent with refine=true.

Indeed it is

[Shalmeneser]

Zero-dimensions are evil
Use Sketcher_ConstrainVertical instead or Sketcher_ToggleConstruction lines (in blue).

[Shalmeneser]

You should set Refine=True in the last Pad, before filleting.

Where can I find it?

Two faces in the same plane should/could be fused (Refine=true). In your file, faces in the same place remain distinct.
Fillet prefers to work in the same face / or not.
.
.

Should I always use it?

Big question !
Small answer : that depends !

[TomD]

Thanks man, I would never have found it without your help.
Stuff like this is why I find FreeCAD difficult to recommend to others

For future reference: his link showed me where I could find this Refine functionalty.
https://forum.freecadweb.org/viewtopic.php?f=3&t=57612

Also, I didn't use the Sketcher_ToggleConstruction lines in my sketch. At least not intentionally. I only learned they exist last week or so. Vertical constraints are much more intuitive.

[Shalmeneser]

For future reference: his link showed me where I could find this Refine functionalty.
https://forum.freecadweb.org/viewtopic.php?f=3&t=57612

There is a lot of discussion in the forum about Refine as solution or problem.

[Shalmeneser]

Try to be logical into your sketches.

Here :
* right blue line to reduce the usefull part
* symmetries to center everything
* blue square to fix little holes
* equality for equal dimensions

The less dimensions the better.