SMEdit is widely used, and is hugely supported.
It comes with tons of abilities right at you fingertips.
It also allows you to do more than just modify. You can also create your own blueprints. SMEdit is proud to be the first station and shop editing tool.
3D modeling import abilities include obj, binvox, VRML, and Minecraft .schematic!
If you wish to talk to me directly about SMEdit you can join me directly most of the time and most days on my community teamspeak voice chat. Just be ready to use push to talk on there as it is forced on the voice chat.
The site for SMEdit will be back up when I get a chance to focus on redoing it.
Here is a nice tutorial by Unbreakable Gamers
17th of July, 2019: SMD is currently under maintenance, the site may go down while we are working on it. Apologies for the inconvenience.
Multipurpose editing tool; Blueprint modifier / creator able to import 3D files