Winter of Quality 2026
During the 2025–2026 winter (northern hemisphere), Blender developers focused on quality and stability. This blog post offers an overview of the work accomplished.
Bugfixes
Between December 1, 2025, and January 31, 2026, more than 350 reported issues were fixed. Here is a per-module breakdown of the fixed reports:
- Modeling: 58
- VFX & Video: 53
- User Interface: 50
- Nodes & Physics: 37
- Viewport & EEVEE: 35
- Sculpt, Paint & Texture: 24
- Render & Cycles: 20
- Grease Pencil: 22
- Animation & Rigging: 16
- Python API: 7
- Asset System: 9
- Core: 14
- Pipeline & IO: 8
- Platforms & Builds: 2
Additionally, many old reports have been double-checked and either fixed or closed (for example, if the issue could not be reproduced in a recent Blender version). Issues that were not reported by users were also addressed.
Module Work Overview
In addition to fixing bugs, developers also spent time tackling technical debt, updating documentation, writing tests, and stabilizing certain areas of the code.
Animation & Rigging
Work included removing Legacy Action code, improving animation system performance, adding benchmarks, and adding an operator to swap actions on multiple datablocks. Developer documentation was also updated.
Compositor
Refactors moved toward reusable node trees for efficient evaluation. Over 40 fixes for bugs and known issues were completed.
Core
Developers refactored C++ data structures for type and memory safety. Depsgraph tagging instances were reduced by approximately 10% using the legacy value of “0”.
Modeling
Fixed display issues for fonts with self-intersections. Added redo support for Edge & Vertex slide, Extend Vertices & Loop Selection, and Apply scale normal flipping.
Nodes & Physics
The transition to the “Attribute Storage” format for mesh attributes was completed. This enabled optimizations to optionally store attribute arrays as single values. Node tools were also refactored to register a separate operator per tool.
Platforms & Builds
The GHOST API was modernized from C to C++, removing the C API and opaque types. DevOps and Buildbot repositories were consolidated into a single public repository.
Render & Cycles
Render kernel lighting was refactored for performance and future changes. RNA C++ abstraction was removed. Automated tests were added for viewport, animation, and preview rendering.
Sculpt, Texture & Paint
A wide range of tests were added for brushes and non-brush operators. Global undo support was added for Texture Paint. The paint stroke system was refactored across all paint modes.
User Interface
Automated tests were added for stacked full/maximized-screen handling. UI code was refactored from C-style to more modern C++-style coding.
Viewport & EEVEE
More relevant render tests were added to the EEVEE and Workbench test suites.
Video Sequence Editor
Focus was on code cleanups: converting more code to C++, splitting runtime data from DNA data, and splitting large source files. Some changes were user-facing, such as renaming strip time-related properties and fixing memory leaks in Audaspace integration.
XR
A separate XR-specific context was implemented.
Statistics
Total closed bug reports: 106. Resolved bug reports: 52 (of which 17 were high severity). Total closed general tasks: 11. Oldest closed task: 6 years, 3 months. Average age of closed tasks: 0 years, 10 months.
Future Quality Projects
After two years of having a dedicated quality period at the end of the year, this may be the last time this specific event is held. The plan is to shift towards a per-module/project technical debt catchup every now and then.