NOTE:Since BC 3.4.2 the builder is currently disabled due to major bugs (Yes it is still disabled in the current version). The filler is therefore the only useful machine mentioned.
These machines are needed to automatically build structures. Whether you want a large box, or a monument to pixel art, one of these will do it for you.
Builders require templates, and the Template Drawing Table is needed to fill in the templates with building instructions. Buildcraft 2.x only
A Template will store block position information only, so builders can recreate simple structures again and again.
The architect table creates Blueprints and Templates for the Builder. Blueprints can place exact blocks instead of whatever the builder is given. Buildcraft 3.x only
A Blueprint will store block type and position information, so builders can recreate complex structures again and again.
The filler can clear areas, fill them in, or box them in, depending on the pattern you set it to.
Given some power and materials, the builder will recreate any structure from a template or blueprint. Disabled due to bugs in Buildcraft 3.4.2