Why CAD is Used rather Than Manual Drafting

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The full form of CAD is Computer Aided Design. There are many reasons why CAD is used rather than manual drafting; the ten most important among them are discussed below.

  • Three Dimensional Modeling: Creating 3D models manually is a very difficult and tiresome job. 3D CAD packages have many more powerful features for creating the 3D models easily.
  • Easy to Modify: Modifying the CAD geometry is easy; you will always have “copy”, “cut”,paste”, “delete”, “move” or some similar editing options available with each of the packages.
  • Easy to Reproduce: Draftsmen used to take days to complete a drawing by manual drafting, and reproducing the drawing meant recreating the drawing from the beginning. But, in case of the CAD, you can reproduce the drawing in no time and make as many copies as you want.
  • Computer Aided Manufacturing (CAM): The 3D CAD geometry is used as input for the CAM packages for generating NC codes. The manual drawings cannot be used for CAM packages.
  • Computer Aided Engineering (CAE): The 3D CAD geometry is used as input for the CAE packages. The CAE packages can simulate the loading conditions and tell whether the CAD geometry can withstand the real loading or not. The drawings created manually cannot be used for CAE.
  • Simulation of the Mechanisms: The 3D CAD geometry can be used for simulating the mechanism, thus you can check the functionality of a machine without investing in prototype building. Manual drawings cannot be used for mechanism simulation.
  • Database Creation: The CAD files can be used to create a PDM/PLM database. Once created, the CAD database can be accessed through a wide area network. The drawings created by manual drafting can only be stored locally.
  • Logical: CAD models or geometry entities are logically connected, or in other words you cannot create a CAD model which is not possible practically. The drawings created by the manual drafting method do not have such checks, and you can create anything.
  • Environment Friendly: Manual drawings are necessarily created on paper, but the CAD drawings can be stored and used electronically without using paper.
  • Access Control: Some of the drawings and design documents are very crucial for a company’s business, and such drawings should not be accessible to all. Providing access controls of such drawings are easy for the CAD drawings, and the access level can be defined for each CAD drawings. Strict access control and maintaining confidentiality is difficult for the manual drawings.


All the advantages of the electronic documents are available with CAD geometry, but that is only one of the reasons why CAD is used rather than manual drawings. The CAD packages, especially the 3D CAD packages, come with many more advantages, but the most important among them were discussed in the article.