When comparing Paint3D vs Sproxel, the Slant community recommends Paint3D for most people. In the question“What are the best voxel editors?” Paint3D is ranked 4th while Sproxel is ranked 11th. The most important reason people chose Paint3D is:
Has a free trial version and a cheap full version.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Affordable
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 Multiple export options
Exports to OBJ, MTL and 3MP.
Pro Free, open source and cross-platform
Sproxel is a free voxel editor that's available for Window and OSX. It's licensed under the New BSD License with source code available here.
Pro Intuitive UI
Cons
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.
Con Abandoned
Hasn't been updated since 2012.