JustVoxel is a simple voxel editor. It uses retained-mode and hidden face removal to improve the performance. A flat shader is also used to make it look more realistic.

Supported features:

• add, delete, and paint both a voxel and a face
• mirror editing of x-axis and z-axis
• undo and redo
• quick color selection by Alt+LMB on any voxel
• perspective and orthographic projection

https://youtu.be/JhHhxDTEHxY