Hi Ed,
> You have a curve and you can modify it by
> control points but control points that are over the
> curve like when you draw a trough points curve
One of the problems with that kind of an approach (editing by points constrained to be directly on the curve) is that it tends to introduce wiggles.
You can see a good example of this kind of problem right in that first video that you linked to - the operator started with a curve like this:
Then there was an adjustment made to a point in this area of the curve:
But notice that this other area further along the curve got a bulge in it, where it actually pulled a fair distance away from the original shape which was previously hugging right along that background line:
So they had to add in another point to take care of the bulging that was a side effect from editing the first point. That kind of fighting against bulging is something that tends to go along with that kind of an editing approach, it's one of the main reasons why I have not tried to make an editing system like that in MoI.
In the Inventor video you may notice that he uses very simple curves in there, mostly with just 3 edit points on them. That editing method does work pretty well with a small number of points in them, but then gets frustrating when trying to work with curves made up of more points than that.
Editing the control point hull like MoI is focused on doesn't put so much pressure on the curve to make it forced to go through each point - that lesser amount of forced pressure on the curve helps to make the edits avoid bulging side effects in other nearby areas of the curve. So that's why editing by moving the hull points tends to be a better system.
- Michael |
