Freecad 0.17 tech Draw missing lines

[Turro75]

Hi All,

I'm struggling with curved lines on 2d views.
I read that this was an OCC bug that should have been resolved in the latest 0CC 7.0.
the test017.fcstd contains an object that failed to show severals rounded lines, now I installed the latest 0.17 which includes the newest occ but even if it seems a little bit better, there are still some missing lines.
I'm not 100% sure the installation I did was successfully as I kept the old 0.16 still active (assembly2 is really important to me), could someone confirm me if the techdraw fails to show the 2D view in the correct way?

Thanks in advance

Valerio

OS: Windows 7
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.17.8203 (Git)
Build type: Release
Branch: master
Hash: ff5869acae44791c03ca604ae88438d72a46f06f
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.0.0

[sgrogan]

Hello Turro75! Welcome to FreeCAd and the forum
Unfortunately I can confirm the problem
issue #2383 seems to show there are still some issues.
OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.8226 (Git)
Build type: Release
Branch: master
Hash: 892271c0d5c421b4fe3a690c8c0c3f7e73dc22f5
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.0.0

[Turro75]

Thanks a lot sgrogan!

sad to see the 2d still useless due to a 2014 bug.

somebody knows if compiling or just installing 0.15/0.16 with occ 6.3 (which seems the last working release) could work?

Ciao

Valerio

[sgrogan]

sad to see the 2d still useless due to a 2014 bug.

I don't know for sure but users have reported being able to clean this up using Inkscape after export.

[triplus]

Hi Valerio!

I read that this was an OCC bug that should have been resolved in the latest 0CC 7.0.

No the issue was not resolved in 0CC 7.0:

viewtopic.php?f=3&t=16876&p=133477#p133473

sad to see the 2d still useless due to a 2014 bug.

Well i wouldn't say current 2D support is useless. I opened the file you attached and 99% of the drawing geometry looks OK to me. Therefore it comes down to adding an arc or two to finished drawing in post-processing phase. Exporting drawing to SVG and adding missing arcs in Inkscape as suggested by @sgrogan is a simple and viable solution. Or you can always do that in FreeCAD once you gain more experience:



A few days back my printer decided not to cooperate and i needed to print some technical drawings and send them to manufacturer. I took pencil and corrected non printed parts and it worked. Imagine that. But then i realized i didn't really discover anything new as back in the days the whole technical drawing was done like that.

[ickby]

I added a bug report to OCC bug tracker with the attached file, lets see if they take care of it. I would not bet on a fast bug fix
https://tracker.dev.opencascade.org/view.php?id=27782

[triplus]

I added a bug report to OCC bug tracker with the attached file, lets see if they take care of it. I would not bet on a fast bug fix
https://tracker.dev.opencascade.org/view.php?id=27782

Fingers crossed.

P.S. Based on the past experience when properly reporting bug to upstream i would be cautiously optimistic.

[wandererfan]

I added a bug report to OCC bug tracker with the attached file, lets see if they take care of it. I would not bet on a fast bug fix
https://tracker.dev.opencascade.org/view.php?id=27782

Exccellent! Thank you.

I made some experiments with using polygon approximation version of HLR algorithms. Not sure yet what to do with the results as there are some improvements and some regressions.
The current state:

using exact HLR

MissingArcsExact.png (3.42 KiB) Viewed 3238 times

Using polygon approximation (Vertices hidden):

Using polygon HLR

MissingArcsPoly.png (3.44 KiB) Viewed 3238 times

No arcs. Many edges are series of short line segments.

Polygon approximation showing vertices:

polygon HLR showing Vertices

MissingArcsPolywVertex.png (4.86 KiB) Viewed 3238 times

Polygon approximation is actually much slower due to the number of extra edges and vertices that have to be drawn.
This gives us some options if OCC doesn't fix this.

wf

[Turro75]

Hello wandererfan,

could You share what You did in order to get different renderer engines working?

Best regards

Valerio

[wandererfan]

could You share what You did in order to get different renderer engines working?

I changed the code temporarily to use OCC HLRBRep_PolyAlgo(approximation) instead of HLRBRep_Algo(exact).

I guess we could have a setting to control which algorithm to use while waiting for OCCT to fix HLRBRep_Algo. It will be very slow though.

wf