The Building Guide is a block from the OpenBlocks mod. This block is used to assist the user in building perfect shapes. When placed and supplied with a redstone signal, it will place ghost blocks in the world, forming the shape and size defined with the block. The available shapes are: Cylinder, Cuboid, Dome, Triangle, Pentagon, Hexagon, Octagon, and Sphere. The Triangle, Pentagon, Hexagon, and Octagon are two-dimensional, and will only appear on the same y level that the Building Guide is on. Other than these 4 shapes, the shapes are three-dimensional and dynamic. Using a dye on the Building Guide will turn the guide blocks into the color of the dye, and will not consume the dye.
To change the shape of the guide, the sneak key must be held down and an empty hand used on the block. This will cycle through all of the available shapes. To change the size, an empty hand should be used on any of the sides. Using the Building Guide on the South face, bottom face, and the West face will make it smaller in that direction. Using the Building Guide on the North face, top face, and the East face will make it larger in that direction. Two-dimensional shapes can cannot have their size changed on just a single side; it will change the size in all directions.