The project has been dormant for 14 years. I updated it to Java 25 and made some minor changes. It can be used on Linux and Windows. The 32-bit version has been discontinued, but you can try compiling one if you want (good luck with the Jogl and other libraries).
I plan to update it when I have time. The code is open source, so you can fork it and contribute if you want.
The project is under GPLv3, so if you modify it, please share the code.
https://github.com/LuizRafael79/G3D-Editor