When comparing Paint3D vs Goxel, the Slant community recommends Goxel for most people. In the question“What are the best voxel editors?” Goxel is ranked 4th while Paint3D is ranked 6th.
Ranked in these QuestionsQuestion Ranking
Has a free trial version and a cheap full version.
Pro Scripting support
Can be used to generate models, import stuff, animate, etc.
Pro Can export traditional 3D models
Pro Interoperates with 2D paint programs
Pro Supports multiple voxel formats
Pro Easy to use
Pro Uses 32-bit color with real volumetric transparency
Pro Supports both "per voxel" drawing and smooth "sculpting"
Pro Open source
At least somewhat available for GNU/Linux.
Pro Supports procedural rendering
You can script a build for it to render.
Pro Supports .obj
Pro Available on Android
Pro Exports to PLY format
Pro Available in Debian/Ubuntu repository
If you don't have it installed yet, just enter "sudo apt install goxel && goxel" on the terminal, and you will be running it in a few seconds.
Pro Simple Interface
Pro Available on iOS
Works nicely with Apple Pencil.
Con The web site's domain is no longer available
Using the WayBackMachine to get the site's contact email address, I attempted to contact the developer to find out what the story is. There has been no response. The WayBackMachine's last archive date for the site was 11Jan2016. Their cached version of the paint3D.net's forum does not have any post explaining what happened.