Something cool that I have not yet seen ! :)
Circle "tangent" can be draw along the "helpers lines"

Take the Circle "tangent" function
Draw somes "helpers lines"
Clic 2 points on these helpers lines
The possible circles are drawing moving !

Ps Request : "Helpers lines" can be also " Helpers circles"
Seems that will be great :)
Rules and dividers are the bases of geometry :)

> What is the exact name of the curves that is used in Moi :"Through point?"

The method for creating that type of curve is usually called an "interpolated curve". One good reference for this is The NURBS Book, Les Piegl & Wayne Tiller, Springer-Verlag 1995–1997.

You may be able to find something online about "NURBS interpolation".


> Nurbs yes but what about the tangent ?
> or the degre of tension (streching) between 1 point between 2 points?

The version MoI uses creates a tangent automatically. You can edit it later by turning on control points and moving the second-to-last point around.

The tension is actually updated for the next beta release, it will use a type called "centripetal knot spacing".


But the "Through point" method is not really the best way to create a curve for the method that you are thinking, though - because it forces the curve to go exactly through every point, it tends to create wiggles in the curve when you have many points. For creating a curve through many points there is a different process called "fitting" which creates a curve that is guided by the points (to a certain tolerance) but is not forced to go exactly through them. That is usually a better way to get a smooth curve. MoI doesn't expose a way to do this right now, but Rhino does with the FitCrv command.

- Michael

> Ps Request : "Helpers lines" can be also " Helpers circles"
> Seems that will be great :)
> Rules and dividers are the bases of geometry :)

Hmmm. But it's not too hard to just draw a circle to use for such a construction, and delete it after you are done...

A line is kind of a special case since a construction line extends infinitely in each direction so it gives something extra (beyond the automatic cleanup) than just drawing a regular line.

A "construction circle" wouldn't really give very much extra benefit over just drawing a regular circle.

- Michael

> Just for the beauty of the thing :)
> So for the permanent figures
> a nature of the draw (solid, dashed, dotted...)?(as the grid lines)

Yes, I think that this will happen eventually. It would make sense to be able to take any object and sort of "lock" it like this so that it can be used as a construction/reference type object without getting in the way too much.

I'm not quite sure when though.

- Michael

A little not very serious exercice with the Developping curve from a circle
I found the good measure of the perimeter of the circle with only control points, rule and circles :)
So I will can now construc the real curve
But all depend of the "measure" of the distance of your Control points "above" the curve:
are they proportional of something or are they pure random?
I am very anxious :D
Final curve tomorrow :)

Ps Of course I can make the same with only a numeric calculate :)

> But all depend of the "measure" of the distance of your Control points "above"
> the curve: are they proportional of something or are they pure random?

That distance is not random, but it is not really a fixed distance for any single point, because the shape of the curve depends on more than just that one control point, it depends on the surrounding control points as well.

For example, if you leave that one control point in place, but move the one next to it 100 units away, the original control point will now be a further distance away from the curve. The curve at any one spot is affected by several nearby control points.

But the more control points you use, the smaller area of curve is affected by each point. So if you use a fairly large number of points, the accuracy will keep on improving.

- Michael

"Paradoxal gear" : application of the Developping curve of a circle :)
http://maurel.meca.free.fr/Html-EN/index_redir.php?page=http://maurel.meca.free.fr/Html-EN/mechanical-paradoxical-gears.htm
Some videos
(interesting artical inside in french but many images)

Wow, that's a super cool moving statue! Sort of hypnotic...

> Each line is perpendicular from the curve to the circle

It's looking quite good!


> Do you think now that your system of control point "past" to the real curve?

I'm sorry Pilou, I don't understand this one question, can you explain it some more?

- Michael

Just that when you draw the curve with "through point" over the construction points,
than the tension of the nurbs fit the "real" developping curve :)
Seems good, just maybe the first but for that I must take the real image :)
So waiting your background system image :)

> Just that when you draw the curve with "through point" over the
> construction points, than the tension of the nurbs fit the "real"
> developping curve :)

Yeah, it won't fit the true curve exactly, but it looks like it is pretty close.

The next beta the tension is different, it is possible that it might be actually be worse for this type of case, if it seems worse let me know and I can maybe figure out some option to help control it a little bit.

- Michael

for the V1?
Something for manage the numerous objects (layers, freeze, group,......
AI 2D format ? (not copyrighted? )
And background image will be possible integrated in a Plan 3D?
So possible to rotate :)

See you the next year and have happy codding !

Hi Pilou:

> for the V1?
> Something for manage the numerous objects (layers, freeze, group,......

I'm not sure... Certainly I will work on this sometime in 2007 but possibly not for the initial V1.

Please realize that it's not the end of the world if every feature doesn't make it into the first release! :) V1 is a beginning, not the end - after the first release I will of course continue to add and improve things.

I want to work very carefully on areas like this that require a large amount of UI work.


> AI 2D format ? (not copyrighted? )

I think that this will be possible for V1, it will likely be the only other file format added before the V1 release.


> And background image will be possible integrated in a Plan 3D?
> So possible to rotate :)

Yes, this one is planned as well, I actually hope to be able to add this in for the next beta, but I haven't started it yet.

- Michael

From Steph3D :)
Seems "infinite grid" on the "2D view" will be useful

Does he know about the setting to increase the grid size under Grid Snap / Grid options ?

You can increase the Grid sections: to something like 3000 or so to make the grid substantially larger. This setting is from the center to one edge of the grid, so that will create a grid 6000 squares across the full grid.

Is there some project that he's working on where a grid 6000 squares across is not large enough?

- Michael

Yes he knows that :)
I believe, it's more when you arrive to the "end" of the grid
And yes it's for some complex projects like cities or similar for video game