Hi artisanicview, usually "Parametric" refers to something different than Rhino blocks - usually "Parametric" in a CAD sense means that the CAD program maintains a history tree of operations and allows you to go in to that history tree and change parameter values like change the diameter of a hole or change the radius value of a fillet and then have the model be recreated.

Blocks in Rhino are a pretty different mechanism than that - that works more like a kind of object template where you can insert many copies of an object and each copy knows that it is a lightweight copy of the base object template and that helps to keep the file size down for a lot of repeated objects. There is some commonality with updating since you can change the object template and the instances will update to the new object but it's fairly different than editing parameter values of "features" in the history tree like Parametric modeling usually involves.

I do want to have an instancing mechanism in MoI in the future, it's definitely on my radar.

- Michael