#What it Does
This tool replaces a particular kind of node with a rectangular volume of a target node.
Ie, you click on the ground and a 3x3x3 mound of dirt appears, which can be other dimensions, materials, etc.
Limited to only placing a maximum of 1024 blocks, but this can be changed.

#How it Works
The first three inventory slots determine how this tool behaves.
Slot one, two and three determine X, Y and Z dimensions, respectively.
Shift + Left click sets which nodes to replace, and Shift + Right click sets which nodes to replace it with. You can select air by clicking anywhere there isn't a block.
Left-clicking places nodes in the ground, right clicking places nodes on top of the ground.