From a strictly technical assessment, a first level question to ask to determine whether to use AutoCAD or Inventor is whether or not you will be using the software to model and document durable goods. For example, will you be modeling components of a mechanical system such as a transmission, ski binding, copying machine, camera, packaging equipment, etc. If not, forget about Inventor. If having a 3D model is not important then forget about Inventor. If 3D is important AutoCAD or Inventor should both be considered but for creating complex 3D models of mechanical parts and assemblies then Inventor is probably the better choice. Both Inventor and AutoCAD models can be used for NC and engineering analysis although Inventor includes analysis tools (e.g., FEM, CFD, kinematic) that must be addressed with 3rd party products for AutoCAD. If your goal is to model a constructed system such as a building or bridge components than Inventor is not for you. AutoCAD and other CAD products will be a better choice. If P&ID drawings are important to you go with AutoCAD. Do you have special needs for creating formal engineering drawings? If so, AutoCAD has many features for customization.
Another factor to consider beside the characteristics of the products your company creates is what do you suppliers and customer use.
You asked about “diversity of work”. The realm of applications addressed by AutoCAD is much larger than Inventor but, for mechanical part design, Inventor is superior. AutoCAD suffers from being a legacy (old) product and therefore the user interface is clumsy and often cryptic. Just look at the steps involved to make a dashed line. I think the constraint-based aspects of Inventor’s user interface requires the user to have a stronger spatial understanding.
A new user can start with AutoCAD and just think of it as a way to duplicate what they might have done on a drafting board. Inventor requires the user to think about the 3D model they wish to create and how the aspects of the object relate to each other.
If you are unfamiliar with the feature-based solid model technology that is used by Inventor I recommend you try it out before making your decision. Free 30-day Inventor licenses are available.
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