A Free 3D Painting Software
ArmorPaint is a stand-alone software designed for physically-based texture painting and does run on Windows, Linux, macOS, iOS and Android. Drag & drop your 3D models and start painting. Receive instant visual feedback in the viewport as you paint. Check out what’s new in ArmorPaint on its release notes

Developers say the first ArmorPaint 1.0 alpha builds are incoming next. Here is where you can download ArmorPaint and Its source code on GitHub