Release notes 0.19

 Are features missing? Mention them in the Release notes for v0.19 forum thread.

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Older FreeCAD release notes can be found in Feature list.

Python 3 and Qt5
The effort to migrate from Python 2 and Qt4 to Python 3 and Qt5 is essentially complete and most developers have moved to the Python3/Qt5 toolchains.

Undoubtedly there are unforeseen bugs and unanticipated breakages that will present themselves during the next development cycle or two, but any existing dependence on Python 2 or Qt4 will not be supported moving forward. Note that the developers of certain addons have not yet ported to their tools to Python3/Qt5. This may be due to several reasons including lack of support, time, resources, or broken dependencies that may or may not be easily fixed. Individuals interested in the migration of a particular workbench or tool are encouraged to participate in the FreeCAD forum.

Fixed issue with Std Part containers visibility when the viewport is displayed in full screen in Qt5:
 * Set for Qt 5.9 and above; forum discussion, commit 2a1dd8415, and commit 57b3ca6f77.
 * Disabled button support in  for Qt5 to avoid MDI view mode-related rendering artifacts; forum discussion, commit 960d612547.
 * Fixed bug in to avoid a crash when returning from full screen; forum discussion, commit c4e34ed9b.
 * Fixed issue #4088 about the visibility of the origin of a Part changing when undocking the 3D view; forum discussion, commit 1e19ef5be.

Development

 * Merged QtWebEngine support; pull request #1937.
 * New Libpack for Windows with Qt 5.12, OCC 7.3 and Python 3.6; forum discussion.
 * Added support for existing Python virtual environments; pull request #2021.
 * Fixed broken support for "INCH" units when exporting to STEP/IGES formats; forum discussion, commit 1b26173580.
 * Improved import/export compatibility with proprietary CAD systems, when using compressed STEP, or STPZ; forum discussion, pull request #2323, commit 7de89cf62e.
 * Pre-select name filter in the import/export dialog; forum discussion, commit e239994,
 * Fix missing application ID and icon on GNOME/Wayland; pull request #2466.

Known Limitations

 * Black screen due to video card drivers, while running FreeCAD inside a virtual machine; issue #3939.
 * Logitech Wingman USB joystick can cause erratic behavior when spinning and zooming in the view; forum discussion.
 * Gesture navigation is fully supported for Windows but yet to be maintained in Linux and MacOS. Problem: the developer, DeepSOIC, doesn't have a MacOS machine with its special trackpad, and hasn't tested it on Linux either; forum discussion.

App::Link and assembly
After 2.5 years in development, the "Link" object, or more formally, was introduced in FreeCAD. This is a special type of with certain properties that will hopefully allow for doing assemblies easier.

A "Link" allows objects to use another object's data, such as geometry or even their 3D visual representation, in the same or different files. It can be thought of as a thin, absolute clone, or as the same object living into two different "instances". Some functionality offered by a "Link" is already present in some workbenches like Arch and BIM (clones, external references), but the "Link" implementation is at the core level, and thus can be used by all workbenches in different ways.

The "Link" component was thought and developed almost single-handedly by user. The motivations and design implementations behind this project are described in his GitHub page, Link. In order to accomplish this feature, several core changes to FreeCAD were made; these are also extensively documented in Core-Changes.

The history of "Link" can be traced to some essential forum threads:
 * Why an object can only be inside one App::Part? (March 2017)
 * Introducing App::Link/XLink (March 2017)
 * Links (May 2017)
 * Realthunder Link implementation: Architecture discussion (June 2017)
 * PR #876: Link, stage one, context aware selection (July 2017)
 * Preview: Link, stage two, API groundwork (July 2017)
 * Assembly3 preview (December 2017)
 * Merging of my Link branch (June 2018)

Finally, the pull request and merge happened:
 * App::Link: the big merge, old thread (July 2019), pull request #2350 (the BIG merge), LinkMerge branch.
 * App::Link: the big merge, main thread (July 2019)
 * A simple path description of Link, 019, Link stage, Asm3, merge? (August 2019)

The "Link" object prepares FreeCAD for the phase that was scheduled to happen after the redesign of PartDesign in FreeCAD 0.17, which is working with assemblies.

"Assembly3" is an assembly workbench written in Python by realthunder, that makes use of the "Link" functionality. The workbench served as a testbed for the "Link" component during its development. While Assembly3 is still not officially part of FreeCAD, with the inclusion of "Link", it is a matter of time for Assembly3 to be provided as an installable add-on, just like A2plus Workbench is provided currently.

Other additions in the App::Link merge
Beside the introduction of, the "LinkMerge" branch also introduced some changes visible to the user with regards to object properties, expressions, visual selection, and the tree view. These are described in the Core-Changes page.

Other

 * The Draft Wire tool now is called "Polyline" in the menu, instead of "DWire"; all options and functionality remain the same, so this doesn't break compatibility; commit 39e748229e.
 * Undergoing efforts to split tools into their own module file to ease maintenance of the codebase for the future; forum discussion, commit 16c26cb3b1.

FEM Workbench

 * Updated coding standards; forum discussion, commit ad03ee9bdf, commit 27cb54009b.

Part Workbench

 * New Face method: to cut holes into a face. The face usually needs to be validated after operation.

Other Changes

 * Fixed issue #3993, Python 3 memory leak. Forum discussion, commit.

Render Workbench
Added support for Blender Cycles renderer; commit 759067912f.

Sketcher Workbench
Sketcher Elements Widget - Filter geomtry by type (Discussion)

Other

 * There has been discussions about changing the standard behavior of TechDraw. Instead of keeping the drawing pages updated automatically, they would be updated only on demand; this would mitigate the effects of TechDraw slowing down the rest of FreeCAD when modelling. Moreover, now that "App::Link" is included in FreeCAD, TechDraw pages may be stored in a separate file, and loaded on demand; forum discussion (main discussion), forum discussion (alternatives).
 * Fixed font size issues when exporting to SVG; forum discussion, pull request #2219.
 * Fixed regression in caption handling and hide caption property where not applicable; pull request #2228.
 * New page templates, Russian State Standard of Technical Documentation (Unified system for design documentation), GOST 2.104-2006, GOST Р 21.1101-2013; forum discussion, pull request #2249.
 * Added options for page size, line width and background when saving to SVG; this improves Draft/Arch and TechDraw integration; pull request #2455.
 * New panning of the page using the middle mouse button; forum discussion, pull request #2458.
 * Finer control of drawing updates; forum discussion, pull request #2468, commit 5bed53f858, commit b2d8eeeb65.
 * Also new TechDraw Redraw tool to force a drawing page update while ignoring the state of the options "Update with 3d", "Allow page override", or "KeepUpdated". This tool disappeared in 0.18, but was re-implemented for 0.19; forum discussion.