system for hard pencils

Hard pencils are mostly appropriate for drawings requiring accuracy. As we have pointed out previously, such drawings are usually done by engineers, industrial designers, graphic designers and architects. The final drawings they produce have to be to scale and precise so that other people, such as craftsmen, can follow the instructions to construct or make the designed object. These drawings come in a number of different types of perspective, or parallel projection systems, ranging from flat orthographic plan or elevation drawings to 3D perspective illustrations.