Up to now, when working in AutoCAD, we were forced to create the model we thought would be final as accurately as possible. The geometry and dimensions should have been previously studied and probably sketched on paper, just as we did before there were computers and CAD systems.

With parametric design is now possible to create a rough sketch that will be adjusted after adding the geometric and dimensional constraints needed to reach the final solution. We even have the opportunity to work with the precision to which we are used to, but allowing the application to infer and apply the appropriate geometric constraints, which will finally produce a model that incorporates the advantages of parametric design.

In the exercise we propose in this video we start with an extreme situation, which surely does not respond to the normal way of working but that in my experience allows students to understand the meaning of geometric and dimensional constraints. The initial drawing contains three arcs and four lines randomly placed in the viewport. Applying a series of restrictions will create a triangle with rounded corners that holds its shape when its height changes.