Wings 3D is a free, open-source 3D modeling application used by professional 3D artists, illustrators, and hobbyists. It offers a wide range of features including subdivision modeling, a powerful polygon bridge tool, multi-resolution sculpting, and advanced UV unwrapping and texturing. Wings 3D is easy to learn and offers a simple, intuitive interface for quickly creating 3D models. It is also highly customizable with a wide range of plugins, scripts, and other add-ons that enhance its capabilities. Wings 3D is compatible with Windows, Mac OS X, and Linux operating systems. It also supports a range of popular 3D file formats such as OBJ, STL, and 3DS.
Discontinued According to the official website k-3d.org: The latest version of the "source code" is from November 2015. And the latest binary executable version is even older. According to its Sourceforge page (https://sourceforge.net/projects/k3d/files/K-3D Win32 Binaries /), the latest version is from June 2010.