Blender's UI and Runtime: Much Faster Than GPUI

BUI is a standalone user-interface library that extracts Blender’s widget drawing and interaction rules into a small C runtime, without requiring Blender. Applications build a widget tree through bindings for Python, Rust, JavaScript and React, C/C++, or Dear ImGui; the runtime handles layout, input, rendering, and window presentation on the CPU or GPU. Its central argument is that Blender’s interface combines a distinctive, familiar feel with efficiency, and that other desktop applications should be able to use both. BUI aims to redraw only changed areas, remain idle when nothing is happening, and start quickly.

The library offers several entry points: existing Tkinter programs can run unchanged, Python developers can use Blender-style components or partial Qt-compatible syntax, and Rust and JavaScript developers can build native interfaces with HTML-like markup and CSS rather than a browser. Features include Blender’s draggable numeric fields, expression evaluation, fuzzy menu search, undo and redo, pie menus, color tools, editors, and dark and light themes. The README describes broad language and widget support, while noting that some integrations are partial or still forthcoming. The repository’s tagline claims BUI is twice as good as GPUI, and its contents include a performance section on startup, battery use, frame times, and benchmarks; the supplied material gives no benchmark figures to assess that comparison.