Hi Adam,

> Perhaps something like this CoCreate example ?

No, actually not like that at all.

When you watch the video that you linked to, notice how the editing done there is all of a localized nature - the operations done in there are things like pulling control points of the surface around or pulling isoparms (which is sort of like pulling a row or column of control points at once).

That's a much different kind of editing than what can be done with history. Both kinds of editing are certainly useful but history can allow for some more really broad shape changes with a smaller amount of editing effort for the right kinds of circumstances.

Here I'll give an example to help illustrate the difference for you.

Here I have drawn 3 curves in the Top view:



Then I created a piece of intestine using the circle as the profile, the inside path as the sweep rail, and the outer one as the scaling rail:



In the 3D view the shape looks like this:



Now I'm going to go in and edit just one point of a curve - the control point here on the profile curve that was used to generate the sweep:



I pulled that one point downwards:



And note what a broad sweeping change results from that one curve control point edit:



Now combine that with editing the rail and/or scaling rail curves...

One particular thing to note is that the original rail and scaling rail curves have a much more simple control point structure than the complex surface that was generated by the entire sweep.

It's much more difficult to do direct editing of control points of the resulting surface in things like this, but with history you can just edit the 3 curves you originally drew and have the model update.

And note that here you don't have to switch to some totally different set of editing tools, you just use curve editing tools to make things happen. In the video you linked to, notice that the direct surface editing tools are a whole different toolset from what was used to create the model initially. Multiple different toolsets is not a reduction in complexity, it's added complexity.

Now don't misinterpret what I'm saying - I don't think that direct editing is bad, just that it does not do all the exact same stuff as history editing.

- Michael