Corner appears cut

[NewJoker]

Hi,

for a long time I've been puzzled as to why one corner of even very simple model such as cuboid always appears cut when I zoom on it:

corner.JPG (16.75 KiB) Viewed 1346 times

I can even select this artificial face but it disappears after exporting to STEP file. Do you know what causes this distortion and if it can be fixed somehow ?

This happens in both 0.19 and 0.20 but here's my FreeCAD info for the former:

OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24276 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: a88db11e0a908f6e38f92bfc5187b13ebe470438
Python version: 3.8.6+
Qt version: 5.15.1
Coin version: 4.0.1
OCC version: 7.5.0
Locale: Polish/Poland (pl_PL)

[bambuko]

It's always easier if there is a FreeCAD file to examine?
otherwise it's guesswork?
(although I am sure ubergeeks here will know the answer just from attached picture)

[NewJoker]

It's always easier if there is a FreeCAD file to examine?
otherwise it's guesswork?
(although I am sure ubergeeks here will know the answer just from attached picture)

Sure, I can provide the exemplary file. Here's a simple model of a cuboid that has this issue:

Corner distortion.FCStd

(9.08 KiB) Downloaded 32 times

[adrianinsaval]

Long existing visual glitch in FreeCAD, no idea what causes it but your model geometry is not affected, it's a rendering issue

[Shalmeneser]

Part_CheckGeometry :
Checked object: Corner_distortion.Pad (Pad):
Shape type: Solid
Vertices: 8
Edges: 12
Wires: 6
Faces: 6
Shells: 1
Solids: 1

Nothing unusual. Just visual distorsion imho.

[bambuko]

... it's a rendering issue

How do you pick/select a vertex on affected corner? (I haven't managed so far...)
later edit: you can actually select affected vertex by zooming far out
Problem disappears if you shorten the pad from original 500mm to 330mm (or less).
Anything above 330 shows the "cut corner"
Why this one corner, but no others?

BTW, it's not just 0.19 and 0.20 - I have the same problem in Link branch

[NewJoker]

All right, thanks. I assumed that it’s not harmful to the model (apart from the fact that this corner can’t be selected) but I wondered if you know what causes it and if it can be fixed. Does it happen for everyone or only for some users ? Maybe specific hardware or OS configurations are affected by this glitch.

[Shalmeneser]

Same visualization problem

Code: Select all

OS: Linux Mint 20.2 (MATE/mate)
Word size of FreeCAD: 64-bit
Version: 0.20.26683 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 0388fbc)
Hash: 0388fbc98d49d874fb341b9037a743bc691d501f
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.3
Locale: French/France (fr_FR)

[Chris_G]

All right, thanks. I assumed that it’s not harmful to the model (apart from the fact that this corner can’t be selected) but I wondered if you know what causes it and if it can be fixed. Does it happen for everyone or only for some users ? Maybe specific hardware or OS configurations are affected by this glitch.

I think it comes from the default configuration of the 3D scene camera.
I have that kind of glitches from time to time and usually fix it with a View_FitAll.

I can even select this artificial face

In fact, I think the glitch is a hole, and you are selecting another face of the solid, that is in the background.

[TheMarkster]

Werner explained it once, but I don't remember the details. As ChrisG has said, view -> fit all will fix it. I see this also sometimes as an inability to select a vertex, also corrected with view -> fit all.