I heavily modified xen-42’s tutorial to create a Minecraft-style block-building system without a grid. I’m calling this concept a Voxel-Lite.  Find updates on my website:
noah-chase.com
Placing blocks is a bit smudgy from some angles, but I plan to make it nice and crisp. Also, this is the project’s first iteration, so nothing is polished—especially terrain that’s further out!
xen-42’s tutorial can be found here:
Controls:
Mouse: Look
WASD: Move
LMB: Break / Hit
RMB: Place / Block
1-9: Block Type Selection
T: Toggle Torch
Simply download and run the VoxelDemo_1.exe file.
Don’t fall off the world 🙂