> So it's better to draw out a curve "curve" by the function "Extend"
> than by an tangent aligment to the control's points :)

I'm not sure about "better", these do slightly different things. Extend will not change the shape of the existing curve, it will add a line segment to the end of it (except if it is an arc, it will create a bigger arc in that case). This is the equivalent of drawing a line off the end of the curve that is tangent to it, and then joining the line and the curve together. Except if your starting curve is a line it will make a single new line in that case.

When you move a control point, the shape of the curve will change, but if you keep the points aligned in the same direction the end tangent of the curve will be the same.


> Ps Is it possible to have somewhere the Zoom status? (with some decimal numbers :)

It's a little bit hard to add this in quickly because that's a piece of new UI that has to go somewhere. Eventually I think there needs to be some view properties dialog that will let you see and change a few different things about the view, including zoom factor.


> I made some mouse's wheel actions before see a "divergence" :)

A very small divergence is normal in many cases. Some operations such as intersections are calculated to the modeling tolerance value, which by default is 0.01, so it is not unusual that there will be gaps and things when you zoom in tighter than that. Also just mathematics in general is limited on the computer since there is only 8 bytes of data to hold each number. So the range of numbers that can be expressed is limited and this inherently creates small errors just from adding and multiplying numbers together. If you zoom in tight enough you can see these kinds of very small divergences as well.

That's why many things work with a tolerance value, like for instance join will join together two curves if their ends are within the modeling tolerance of each other, they don't have to be exactly touching with 0 divergence.


> What is the "clickety clack zoom dimension" of a wheel action?

One clickety clack will adjust the zoom factor by 0.8 in the top/front/right view. In the 3D view it is slightly different, it doesn't change a zoom factor there instead it moves you by a percentage of the distance between the eye point and the pivot point.


> PSs Have you plan an "intersection Snap On" with a surface when you start a line ?

Probably eventually. But this is a somewhat difficult area since the intersection with a surface is a fairly intensive calculation, so performance is a concern there. That's why I haven't attempted to do it yet.

- Michael