Hi Adam - well, history is a pretty simple concept - just tweak operations that you have done previously and see the result update.

I'm not sure why that seems like a very complex idea at its heart?

Certainly when parts get very complex that can involve quite a lot of steps to be replayed and doing more direct surface manipulation can be good to have in that case as well.

But you need to realize that direct editing can't perform all the same kinds of operations that history can, because the direct editing mechanisms need to do a kind of reverse engineering of the geometry. That's not particularly feasible for many kinds of freeform surfaces, things like a sweep with a scaling rail modifier applied to it cannot really be automatically reverse engineered, so for example none of the existing direct modeling systems (despite having a tremendous amount of effort and man years invested in them) would be able to recreate the original rail curve and scaling rail for tweaking a freeform one-rail sweep. That's just one example.

Those kinds of direct modeling systems that you are referring to are very focused on handling more conventional MCAD features like extrusions, revolutions, stuff like that and not just any kind of surface.

> Isn't MoI meant to be (the perfect choice for someone who
> has been frustrated with the complexity of existing CAD tools.)

Yup, it certainly is - and certainly doing an automatic recording of your modeling steps to build the history without needing to do any kind of special steps would fit into the low complexity and easy to use category. I don't really know why you would think otherwise??

- Michael