Let’s critique AutoCAD’s parametric constraints

One of the big-ticket features of AutoCAD 2010 was parametric constraints. This was old hat for many applications, even some based on AutoCAD like Mechanical Desktop. Parametrics and constraints already existed in vanilla AutoCAD in the guise of dynamic blocks, but this was the first time ordinary AutoCAD allowed ordinary AutoCAD objects to be constrained and linked to parametric dimensions. Contraints mean that you can draw some objects and tell them that they are only allowed to behave in certain ways. For example, two lines have to remain parallel to each other. Parametrics mean that objects can be tied to special dimensions such that the dimensions drive the objects, not the other way round. How good a job has Autodesk done with creating and improving this feature in AutoCAD? Has Autodesk done its usual trick of releasing a half-baked feature and then ignoring it to death? In one vital respect, the answer is a resounding yes. AutoCAD’s parametric constraints can only be applied to 2D objects. Draw a shape using a polyline, apply constraints and parameters, and adjust them to make things work properly and appear correctly. Now extrude the polyline to convert it to a 3D solid. Your carefully applied constraints and dimensions are instantly exterminated. This was a huge and obvious hole in the feature when it was introduced, but on the fourth iteration of this feature in AutoCAD 2013, that gaping hole remains resolutely unfilled. I guess Autodesk is keeping AutoCAD’s parametrics in this flattened state in order to protect Inventor from internal competition. This 3D failing is very obvious, but I’m interested in more subtle aspects than that. As my experience with parametrics in other applications is limited, I’d like to encourage you to provide us all with the benefit of your knowledge. How does the AutoCAD 2013 implementation compare…

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