Left-click or drag to affect single voxels for free editing.
Create a straight line by left-click then dragging the mouse and release.
Left-Click and drag to modify voxels in a rectangle from the perspective of the screen.
Left-Click and drag to modify voxels in an ellipse from the perspective of the screen.
Affect block of voxels using left-click then drag to size and release.
Left-click to affect contiguous voxels by 'filling' them with the same colour.
