[Problem] CAM: 3D surface line pattern doesn't cut full width

[marshr32]

Is there an existing issue for this?

• I have searched the existing issues

Forums discussion

https://forum.freecadweb.org/viewtopic.php?f=15&t=68335

Version

0.20 (Development)

Full version info

OS: Windows 10 (10.0)
Word size of FreeCAD: 64-bit
Version: 0.20.28567 (Git)
Build type: Release
Python 3.8.13, Qt 5.12.9, Coin 4.0.0, OCC 7.5.3
Locale: English/New Zealand (en_NZ)
Installed mods: 
  * A2plus
  * CurvedShapes
  * Curves 0.4.2
  * sheetmetal 0.2.49

Subproject(s) affected?

Path

Issue description

Detailed description and pics in the linked forum post, but briefly.....

When a cut is generated using the line pattern it will produce a part that is over or under dimension depending on the stepover value that's selected vs the width of the cut.
It will not produce a final path in the series that's less than the specified stepover to cut to the exact dimension.
The 2D pocket tool does produce this last path with smaller stepover, so I think it's a bug in the 3D surface code.

Anything else?

In this case the stepover on the finish op is set to 13% and the total width of the cut is 1.4mm smaller than it should be.
If the stepover is changed to 12% it's nearly perfect, but it takes a lot of playing to find the correct stepover value manually vs how it's done with 2D pocket where a path with small stepover is added automatically.

stepover example.zip

Code of Conduct

• I agree to follow this project's Code of Conduct

[luzpaz]

Please x-post this ticket to the forum so users know this is getting tracked. (also prepend the ticket number to the thread summary). thanks!