Engineering tools are tools used to make engineering work easier. These tools can range from basic items such as hammers, power tools, and computers to complex items such as 3-D printers, CAD software, and solar energy technology. Engineers use these tools to create, modify, and maintain engineering projects. For example, hand tools are commonly used for constructing or repairing structures and machines, and power tools are commonly used for grinding, cutting, drilling, and forming materials. Computer-aided design (CAD) software is used to create engineering plans, while 3-D printers are used to manufacture parts to exact specifications. Additionally, renewable energy technology such as solar panels, wind turbines, and geothermal energy systems are common engineering tools that are used to create clean and efficient energy sources.